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Service manual I Section 2(23) 

Cl Fuel System 

Repairs B27B28E,F 

and maintenance 2601975-1983 



VOLVO 



^ books4cars.com 

4850 37th Avenue South 




Note: new inlet manifold introduced in 1979 - 
same type as fitted to B 27 F models. 



The information included in this manual concerns the Cl fuel system fitted 
to the following engines: 

Engine Type Model year 

B 27 E 1975-1980 

B 28 E 1981-1983 

B 27 F 1976-1979 

B 28 F 1980-1982 






Volvos are sold in versions adapted for different markets. 
These adaptions depend on many factors including legal, 
taxation and market requirements. 

This manual may therefore show illustrations and text 
which do not apply to cars in your country. 



1 



Order number . TP 30592/1 

Supersedes TP 11122/3 (USA. Canada) 
TP 1 1 543/1 (Other markets) 



We reserve the right to make alterations. 



Group 23 Fuel System 
Contents 



Contents 

Operation Page 

Specifications 2 

Special tools 12 

Cl-System 

Brief description 

Location of components 

Important information 

Flushing system A 1-18 

Inspection of system B 1-45 24 

Faults detected B 46-63 40 

Adjusting line and rest pressures B 64 47 

Fault Tracing C 1-2 48 

Components, checking and replacement etc 

Tank pump 0 1-10 50 

Fuel pump + non-return (check) valve D 1 1-18 55 

Fuel accumulator 0 11-18 55 

Fuel filter 0 19-21 60 

Air-fuel control unit 0 22-65 61 

Injectors 0 66-75 73 

Control pressure regulator D 76-79 76 

Start injector, thermal time switch, impulse relay D 80-92 77 

Auxiliary air valve 0 93-95 81 

Relays D 96-98 82 

Wiring diagram El-5 83 

Constant Idle Speed System (Cis-system) 

Location of components 86 

Idle speed 87 

Fault symptoms 87 

Basic setting and inspection of system FI-14 88 

Fault tracing G 1-11 92 

Wiring diagram HI 95 

Idle speed & CO content, 
checking/adjusting 

General J 1-2 96 

B 27 E 1975-1978 J 3-7 97 

1979-1980 J 8-15 98 

B 28 E J 8-15 98 

B 27 F J 16-30 100 

B 28 F J 16-30 100 

Miscellaneous 

Air filter, air preheating K 1-4 105 

Fuel lines, replacing nipples K 5 107 

replacing lines K 6-14 107 

connections K 15-19 110 

Fuel tank 1975-1978, types K 20-22 1 14 

replacement K 23-43 116 

1978-1983 K 44 122 

Evaporative system K 45-54 123 



Group 23 Fuel system 
Specifications 



Specifications 

PLATES AND DECALS 

Only those plates which contain information concerning the Cl-system are included in this section. 




USA/Canada 

-1980 VC 264 £5 L 1 000000 
1981- Y VI BX 69 4 X B 1 QOQQQO 



Ovriga 

-1980: 



26 5 fil LI 000000 
YV1 264 68 IB 1 QOQQQO 

T T 

Engine type Chassis number 



Model year 
designation 





Model plate 

Located on front right inner wing/fender. 

Also includes type designation. 

Notel Type of plate depends on model year. 1981 plate 
shown adjacent. 



Vehicle identification number 

USA and Canadian vehicles only. Visible from outside 
of vehicle. 

- 1979: left windscreen/windshield pillar 
1980-: top of dashboard. 



Vehicle identification 
(type designation) 

Note! Number coding varies with model year and 
market. Numbers shown adjacent are only intended 
as examples. 



Engine type Model year designation 



61 = B 27 A B 

62 = B 28 A E 

64 = B 27 E H 

65 = B 27 F L 

68 - B 28 E M 

69 = B 28 F 



- 1975 A = 1980 

= 1976 B = 1981 

= 1977 C - 1982 

= 1978 0 = 1983 

= 1979 



Engine serial number and part 
number 

Located on a plate in front of oil filter. 8 28 E/F 1981- : a 
decal on rear right end of cylinder head shows last 
three digits of part number. 



Exhaust emmissions plate 

Fitted only to vehicles for Sweden, Australia, USA and 
Canada. 

Located on front left inner wing/fender. 

Contains information on idle speed, valve clearance, 
timing, CO-content etc. 

Note! 

- idle speed not stated on vehicles equipped with con- 
stant idle speed system (CIS) 

- CO-content not stated on vehicles which have a 
sealed CO-adjustment screw. 




Group 23 Fuel System 
Specifications 



CO-CONTENT & IDLE SPEED 

General 

• When checking/adjusting CO-content and idle speed on vehicles with automatic transmission always engage 
neutral “N" and apply the parking brake 

• CO-content should be checked/adjusted when engine is warm and idling 

• If CO-content is not according to specifications ie. check values, it must be adjusted to setting value 

• If CO is according to specifications it is not necessary to adjust the engine providing that it runs satisfactorily. 

E-engines 



Engine 

type 


Model year 


Market 


CO-content 
setting value 
(check value) 


Idle Speed 
r/s (r/min) 


B 27 E 


1975-1977 

1978 

1979-1980 


Sweden + Australia 
Other markets 


1.5 (1. 0-4.0) 
2.0 (1. 0-4.0) 
2.0 (1.0-3.0) 
2.0 (1. 0-3.0) 


15.0 (900) 
15.0 (900) 
15.0 (900) 
15.0 (900)” 


B 28 E 


1981 

1982 

1982-1983 


Sweden + Australia 
Other markets 


2.0 (1. 0-3.0)* 
2.0 (1. 0-3.0)* 
2.0 (1. 0-3.0) 


15.0 (900)” 
15.0 (900)” 
15.0 (900) 



Remarks 

11 Automatic transmission 16.7 r/s (1000 r/min) 
» Pulsair-system disconnected and plugged 



F-engines 



Engine 

type 


Model year 


Market 


CO-content 
setting value 
(check value) 


Idle Speed 

r/s (r/min) 


B 27 F 


1976 




1.7 (1. 4-2.0)” 


15.0 (900) 




1977 


USA California 


0.7 (0.4- 1.0)” 


15.8 (950) 






USA Federal 


1.0 (0.7-1. 3) 


15.0 (900) 






Canada -t- Japan 


1.7 0.4-2.0)” 


15.0 (900) 




1978 


USA Federal + Canada 


1.0 (0.7- 1.3) 


15.0 (900) 






USA Calf. + Japan 


1.0 (0.7- 1.3)* 


15.0 (900) 




1979 




1.0 (0.7- 1.3)* 


15.0 (900) 


B 28 F 


1980 




1.0 (0.7-1.3)* 


15.8 (950) 




1981-1982 




1.0 (0.7- 1.3)* 11 


15.0 (900) 41 



Remarks 

" Air pump must be disconnected and plugged 

" Lambda-sond disconnected. When Lambda-sond is connected the CO-content must drop to less than 1.0% 
91 Sealed CO-adjustment screw, excluding Japan + Canada 1981 
41 CIS-system not fitted to USA Federal + Canada 1981 



3 






Group 23 Fuel system 
Specifications 



Cl-system 



PRESSURES 

450-530 kPa (64-75 psi) 
150-240 kPa (21-34 psi) 

Control pressure, see below 



Line pressure 

Rest pressure, min. 




E-engines 



Control Bosch number 

pressure Volvo number 

regulator 


. . . 005 
269291-1 


... 018 

269531-0 


038 

269837-0 


Engine 

type 


Model year 


X 


X 


X 


B 27 E 


Early type 

Late type Sweden + Australia 
Other markets 


B 28 E 








X 



F-engines 



Control 


Bosch number 


... 004 


... 018 


. . . 021 


... 029 


.066 


pressure 

regulator 


Volvo number 


463971-2 


269531-0 


1219952-7 


269777-9 


1269315-6 


Engine 

type 


Model year 












B 27 F 


1976 

1977 USA 




X 




X 






Other markets 




X 










1976-1977 special version USA 
1978 USA California + Japan 


X 




X 








Other markets 








X 






1979 


X 






X 




B 28 F 


1980-82 










X 








Groep 23 Fuel system 



Specifications 



Control pressure regulator 

Control pressure, warm engine 



cold engine, see diagram 



20-30 ohms 



Resistance 



Control pressure regulator . . . 005 

(regulator with full load enrichment) 

Control pressure, warm engine 

engine off 275-305 kPa 

(39-43 psi) 

engine on 345-375 kPa 

(49-53 psi) 



Control pressure, cold engine, see diagram 

Note! Diagram shows control pressure with engine 

turned. 

Resistance 20-24 ohms 



Control pressure regulator . . . 018 

(regulator with full load enrichment) 

Control pressure, warm engine 

engine off 305-335 kPa 

(43-49 psi) 

engine on 345-375 kPa 

(49-53 psi) 



Control pressure, cold engine, see diagram 
Notel Diagram shows control pressure with engine 
turned off. 




iiiliilliliililii 



Resistance 



20-24 ohms 








HI 



Group 23 Fuel system 



Specifications 



Control pressure regulator . . . 021 

Altitude compensating device incorporated in regulator. Special versions for some B 27 F USA Federal 1976 and 
1977. 

Resistance 20-30 ohms 



Control pressure, hot engine at different altitudes 



The above graphs apply to Bir pressure at sea level and 
up to altitudes of approx 600 m - 2 000 ft (947 mbar or 
higher). For higher altitudes it is necessary to know the 
prevailing air pressure to be able to calculate the correct 
control pressure. 



Control pressure, hot engine at different altitudes 

Tolerance: ±25 kPa (0.25 kp/cm* - 3.6 psi). 



Control pressure regulator . . . 029 

(regulator with full load enrichment) 

Note! B 27 F 1977 California: the full load enrichment 
system is disconnected. Therefore specifications for 
control pressure apply both with engine off and engine 
running. 

Control pressure warm engine 

engine off 305-335 kPa 

(43-48 psi) 

engine on 345-375 kPa 

(49-53 psi) 

Control pressure cold engine, see dia. 

Note! Diagram shows control pressure with engine 
turned off. 

Resistance 20-24 ohms 



6 









Group 23 Fuel system 



Specifications 



Control pressure regulator 

(regulator with full load enrichment) 
Control pressure, warm engine 
engine off 






305-335 kPa 
(43-48 psi) 
345-375 kPa 
(49-53 psi) 



engine on 



Control pressure cold engine see diagram. 

Note! Diagram shows control pressure with engine 
turned off. 



20-24 ohms 



Resistance 



Thermostat 

valve 



Intake 

manifold 



Control pressure regulator . . . 066 

(regulator with cold engine acceleration enrichment) 
Note! B 28 F USA & Canada with pressure differential 
switch: acceleration enrichment system is discon- 
nected via control pressure regolator. 



approx. 53°C <125°F) 



Thermostat closes at 
Delay valve 

delay time 

colour 



approx. 1 sec. 
Grey 



Control pressure 
hot engine 



345-375 kPa 
(49-53 psi) 



Control pressure regulator 



during acceleration (cold engine 
but regulator warmed-up) 



Resistance below 12°C (54°F) 32-38 ohms 

above 18°C (64=F) . . . 16.5-19.5 ohms 



Group 23 Fuel system 
Specifications 



START INJECTOR Type of start injector fitted to vehicle depends on 

model year and engine type. Identification number 
(last 3 digits) is stamped on side of injector. 

Injection time is controlled by the thermal time switch 
(see graph below). 

1981-1983: start injector is also controlled by an im- 
pulse relay so that engine receives additional fuel dur- 
ing warm starts. Impulse relay engages start injector 
after approx. 1.5 secs, which is then followed by injec- 
tion for 0.1 secs., pause for 0.3 secs., injection 0.1 secs., 
pause 0.3 secs . . . 



* Impulse relay can also be fitted to B 27 E 1979-1980. 
B27M97B-1979 and B 28 F 1980. See page 78 




Engine 

type 


Model 

year 


Start injector 


Bosch number 
Volvo number 
Injected quantity 


.400 

269292-2 
165 cnr^/min 


404 

462865-7 
115 cm J /min 


B 27 E 


1975-1978 

1979-1980 


X 


X 


B 28 E 


1981-1983 




X 


B 27 F 


1976-1979 


X 




B 28 F 


1980-1982 




X 



THERMAL TIME SWITCH 




Type of thermal time switch fitted to vehicle depends 
on engine type. 

Temperature at which start injector is disengaged 

B 27/28 E 35'C (95°F) 

B 27 F 15°C (59°F)* 

B 28 F 35°C (95°F) 

* Replacement part 35°C 195^) 




136 600 

Engagement time at different temperaturos 









Group 23 Fuel system 
Specifications 



INJECTORS 




Type of injector fitted to vehicle depends on engine 
type. Identification number is stamped on side of in- 
jector (three last numbers). 



I • Spare pari . . . 013 (1269274-5) 



Injector. Bosch number 

Volvo number 

Opening pressure 

no leakage permitted below 



1975-1978 
. . . 005* 
269184-8 
300-360 kPa 
43-51 psi 
240 kPa 
34 psi 



1979-1983 
. . .013 
1269274-5 
320-380 kPa 
46-54 psi 
260 kPa 
37 psi 



FUEL PUMP 

Capacity at 500 kPa (71 psi), 
12V and 20°C (68‘F) 

Current consumption max. . 



1975-1979 



100 l/h 
(0.8 1/30 sec.) 
9.5 A 



1980-1983 



120 l/h 
(1.0 1/30 sec.) 
9.5 A 



TANK PUMP 

Introduced in 1 977 but may have been fitted to earlier vehicles. 
Current consumption 



1-2 A 




Group 23 Fuel system 
Specifications 



AUXILIARY AIR VALVE 

Not fitted to vehicles with ClS-system 




0 280 140 . . . 



134 740 



Type of auxiliary air valve fitted to vehicle depends on 
model year and engine type. Identification number is 
stamped on end of valve. 

Valve fully open at -30°C » -22®F 

fully closed at +17°C = +158°F 

Valve is electrically controlled and should be fully 
closed after 5 minutes engagement at an ambient tem- 
perature of +20“C = 68° F. 



Engine 

type 


Model 

year 


Bosch number 
Volvo number 
Resistance 


. . . 200* 
269309-1 
15-21 a 


Auxil 
. . . 202 
269532-8 

15-21 n 


ary air valv 
... 213 
1269193-7 
15-21 ft 


• 

...110 
1269319-8 
40-60 ft 


.. . 114 

1266910-7 
40-60 ft 


... 100 

460833-7 
40-60 ft 


B 27 E 


1975 

1976-1978 

1979 

1980 


Man/Auto 


Man/Auto 


Man/Auto 


Man 


Auto 




B 28 E 


1981-1983 








Man 


Auto 




B 27 F 


1976-1979 




Man/Auto 










B 28 F 


1980-1981 










Man** 


Auto** 



' Spare part replacement . . . 202 (269532-81 
• • Auxiliary air valve not fitted to vehicles with ClS-system. 



AIR FLOW SENSOR 

Sensor plate height should be checked at max control 
pressure =» warm engine and fuel pump operating. 



B27E 1975-1978 



B27E 1979-1980 





\ 



10 







Group 23 Fuel system 
Specifications 



Constant idle speed system (CIS) 
CONTROL UNIT 



r' 

r' 




0 280 220 ... 



Type of control unit fitted to vehicle depends on model 
year. Identification number stamped on side of unit 



1981 1982 

Bosch No 001 . . . 008 

Volvo No 1274293-8 1274452-8 



THERMAL TIME SWITCH 




0280130 ... 





Bosch No 028 

Volvo No 1308024-9 



Resistance at different temperatures see graph. 
Suitable test temperatures 



-10°C 32000-53000 n 

+ 20°C 8500-11500 0 

+80°C 770- 1320 0 



11 



Group 23 Cl system 
Special tools 



Special tools 



999 


Description - use 


0976-4 


Flow differential gauge (USA and Canada): flow measurements used with 0977 


0977-2 


Gauge (USA and Canada): setting the air-flow sensor plate. Used with 0976 


2901-0 


Clamping pliers 


5011-5 


Pressure gauge: used with 5032 + 5116 


5012-3 


Pliers: fitting hose nipples. 0 5 & 8 mm 


5013-1 


Pliers: fitting hose nipples. 0 10 mm 


5014-9 


Flow metering unit: checking fuel flow and distribution 


5032-1 


Nipple: connecting pressure gauge 5011 


5102-2 


Wrench: Adjusting CO content 


5116-2 


Hose: connecting pressure gauge 501 1 


5151-9 


Adapter: CO meter (F engines) 


5169-1 


Spanner: removing/fitting fuel tank pump/gauge unit 


5170-9 


Test relay: connecting fuel pump 1978- 


5232-7 


Sealing tool: applying seal (steel ball) to the air-fuel control unit after CO adjustment 


9934-4 


Injector tester 



Note: The 0 sign symbolizes diameter. 



12 





Group 23 Fuel system 
Components 



Cl-system 

Cl System components 

For more detailed information refer to the design (construction) and function service manual 




10 Start injector 



9 Idle adjustment screw 
/ 8 Auxiliary air valve 



11 Injector 



7 Control pressure regulator 



5 Fuel accumulator 



4 Fuel pump 



3 Tank pump 



14 





Group 23 Cl system 
Function 



The Cl system is a mechanically operating fuel injection system with one injector per cylinder. 
Cl is short for 'Continuous injection". The name is derived from the fact that the injectors 
continuously spray fuel i.e. are open all the time the engine is operating. The amount of fuel 
injected is therefore not controlled by variations of the injection time but instead by regulating 
the supply of fuel to the injectors. 

In principle the system operates by measuring continuously the amount of air flowing into the 
engine, and adjusting accordingly the amount of fuel to be supplied. The air flow sensor (1) 
measures the amount of Incoming air, and the fuel is regulated by the fuel distributor (2). 



1. Air-flow-sensor 

Continuously measures the amount of incoming air - 
is an integral part of the fuel distributor. 



2. Fuel distributor 

It controls and distributes fuel to injectors. A pressure 
regulator regulates both line and rest pressures. 
NOTE: A new type of pressure regulator was in- 
troduced in 1978. This new regulator blocks the fuel 
return line when the engine is switched off. 

3. Tank pump 

A tank pump was introduced in 1977 to improve fuel 
delivery - also installed on some earlier models. 

It supplies fuel to the main fuel pump under constant 
pressure and incorporates a non-return check valve 
which minimizes the risk of vapour-lock. 



4. Fuel pump 

Main fuel supply to the system, incorporates a fuel 
check valve to retain (rest) pressure into the system 
when engine is shut down. 



5. Fuel accumulator 

Dampens fuel pump pulsations and maintains (rest) 
pressure in the system after engine shuts down. 



6. Fuel filter 



7. Control pressure regulator 
Regulates control pressure. 

Decreases control pressure during cold start and 
warm-up resulting in a richer mixture. 

There are different versions of regulators (which, for 
example, give a richer mixture during acceleration- 
cold engine), see specifications, page 4. 

8. Auxiliary air valve 

Increases the quantity of air-fuel supplied to the 
engine during cold start and warm-up (fast idle). 
Note! Auxiliary air valve and idle adjustment screw not 
fitted to engines with CIS-system. These engines have 
instead an air control valve. 



9. Idle adjustment screw 



10. Start injector (previously called cold start injector) 

Supplies extra fuel during cold engine starting. It is 

controlled by a thermal time switch (12). 

NOTE: On 1981-1983* models the start injector is 
controlled by an impulse relay. 



* Impulse relay may have been fitted to vehicles manufac- 
tured before 1981, see page 78. 

11. Injectors 

Atomizes injected fuel. 

12. Thermal time switch 

Senses coolant temperature and controls injection 
time of start injector during cold starts. 



15 







Group 23 Cl system 



Location of components 



Location of components 

B 27 E 1975-1978 



Electronic relay 
introduced in 19 











Group 23 Cl system 



Location of components 



B 27 E 1979-1980; B 28 E; B 27 F; B 28 F 



Fuel pump, fuel accumulator 



air valve 



Elctronic relay 
introduced in 1978 







Group 23 Cl system 
Important information 



Important information 




123 264 



Before starting 

Ensure that the vehicle is mechanically and 
electrically sound before checking the Cl system. Cor- 
rect octane fuel supplied by well known companies 
must be used. 

The following points should be checked: 



Mechanical 



Electrical 



Exhaust gas purification 



- compression 

- valve clearance 

- vacuum hoses and connections 

- throttle control and kickdown cable 
(auto) 

- air filter 

- intake manifold (air leakage) 

- exhaust gas system (leakage) 



- spark plugs 

- HT leads 

- distributor cap 

- ignition coil 

- ignition setting, incl. advance 

- all electrical connections 

- constant idle speed system (CIS) 



- crankcase ventilation 

- exhaust gas recirculation 
(EGR) 

- air pump/Pulsair system 

- evaporative system 

- lambda-sond system 

- catalytic converter 








Cleanliness 

Utmost cleanliness should be observed when working 
on the Cl system. 

All fuel connections should be carefully cleaned 
before removal. 

Gaskets, seals 

Always use new gaskets/seals. 




Warning! 

Battery 

It is important when testing the different components 
to ensure that the battery voltage is not too low. 

A battery charger can be connected if necessary. Max. 
charging current 15 A. 

Fire risk 

Extreme care should be taken to avoid causing sparks 
especially when testing the start injector and injec- 
tors. 



134 731 





Group 23 Cl system 
Flushing 



A. Flushing fuel system 



Fuel tank should be flushed if water has (or is believed 
to have) condensed in fuel system. 

Presence of water in fuel system is indicated by 

- engine stoppage 

- difficult cold starting 

- erratic idling 

- low output (poor performance). 



The following equipment is necessary to flush fuel 
system: 

- fuel tank drainer or a large container for collecting 
fuel 

- approx. 6 litres (6 US qts) white spirit (Shell Mineral 
Spirits 135. Shell K30, Esso-Versol or equivalent) 

- two drain pans approx. 1.5 litres (1.5 US qts) each 

- two hoses approx. 1 metre (3 ft) long, to fit to the 
return line and the fuel pump 

- clamping pliers 2901 
-test relay 5170 (1978-)- 




A1 

Clean fuel tank 

Drain fuel and fill tank with approx. 4 litres (4 US qts) of 
white spirit. 

Rock car so that white spirit mixes with sny water 
present in tank. 

Drain tank and refill with clean petrol (gasoline). 




Disconnect tank pump 

Disconnect plug in boot (trunk). 



A3 



19 







Group 23 Fuel system 
Cl-system, flushing 




A4 

Connect fuel pump to a vessel containing white 
spirit 

(at least 2 litres - 2 US qts) 

Block fuel line between pump and tank. Use clamping 
pliers 2901. 

Disconnect line from pump inlet. 

Connect one end of hose (approx. 1 m = 3 ft) to pump 
and submerge other end in a jar containing white 
spirit. 




A5 



Connect return line to an empty vessel 

Separate return line on firewall. Connect one end of a 
hose (approx. 1 m = 3 ft) to return line and submerge 
other end in an empty vessel (capacity approx. 1.5 
litres = 1.5 qts). 



A6 

Install new fuel filter 

If necessary see page 60. 



A7 

Remove injectors 

Place ends of fuel lines in empty vessel (capacity ap- 
prox. 1.5 litres = 1.5 US qts). 



20 






B27E 1975 1978 



B 27 E 1975-1978: Also detach hose from air filter and 
rubber bellows. 



1978-1980 

Connect test relay 5170. 



1981-1983 

Connect test relay 5170. 

Withdraw plug from ignition system control unit. 
Take care not to lose rubber seal in connector. 



Group 23 Fuel system 
Cl-system, flushing 



Prepare start of fuel pump 

1975-1977 

Withdraw plug from air flow sensor. 



Remove air filter 




Group 23 Fuel system 
Cl-system, flushing 





A10 

Flush system 

Turn on ignition to start fuel pump. 

B 27 E 1975-1978: Lift air-flow sensor plate to topmost 
position. 

Other models: Push down the plate until it bottoms. 
Release plate after 1.5 litres (1.5 US qts) white spirits 
have flushed through system. 

Turn off ignition. 



All 

Clean and test injectors 

If necessary see page 74. 

M2 

Install injectors 

Reconnect fuel lines. 



A13 

Install new fuel filter. Reconnect return line 

It is necessary to fit a second new filter because 
some of the water which has condensed in fuel 
system is absorbed by the filter when system is 
flushed. 







22 





Group 23 Fuel system 
Cl-system, flushing 




1978-1980 

Disconnect test relay 5170 and reconnect lead to termi- 
nal 1 on ignition coil. 



1981-1983 

Disconnect test relay 5170 and reconnect lead to termi- 
nal 1 on ignition coil. 

Reconnect ignition system control unit. 

IMPORTANT! Ensure rubber seal is fitted correctly. 
Water entering system will cause corrosion, poor con- 
tacts etc. 



r 



A15 

Install air filter 

B 27 E 1975-1978: also attach rubber belows and hose 
to air filter. 








Reconnect fuel line to fuel pump 
Reconnect tank pump lead 



Fill tank with new fuel 
Start engine. Check for leakage 



A16 



A17 




23 




Group 23 Fuel system 
Cl-system, inspection 



B. Inspection of Cl-system 

Special tools: 2901, 5011, 5014, (alt. 0976+0977 for USA & Canada ), 5032, 
5116, 5170 (1978-) 



Engine must be cold (below +30*C = 86°F) at start of inspection as it is 
necessary to check control pressure, auxiliary air valve and start injector in 
a cold state. 

Notel B 27 F: temperature must be (below 15°C = 60°F) to be able to check 
thermal time switch in car. 



B 27 E 1975-1978 Other models 





Preparatory work 

Operations B1-3 



Remove air filter 



B1 



B2 

Disconnect plug from ignition system control 
unit 

Safety precaution: This is also necessary on some 
models to enable fuel pump to be started. 



B3 

Disconnect connectors from: 

- control pressure regulator 

- auxiliary air valve (not fitted on vehicles with CIS) 



These components must be disconnected or they will 
heat up during inspection and results will be invalid. 

(It can take as long as an hour for a component to cool 
down again.) 






24 








Group 23 Fuel system 
Cl-system, inspection 



r 

r 




Inlet system 

Operation B4 



B4 

Check that inlet system does not leak 

Air must not leak between air-flow sensor and engine. 

Repair as required. 

Check: 

- B 27 E 1975-1978: rubber bellows between air-flow 
sensor and intake manifold. 

- hose connections at auxiliary air valve (air control 
valve) and start injector 

- all vacuum hoses 

- O-rings 

- if all screw joints are tight 

- that injectors are fitted correctly and that rubber 
seals are intact 




Start injector 

Operations B5-10 



B5 

Remove injector 

Allen key 5 mm. 



B6 

Check start injector and thermal time switch 

IMPORTANTI Withdraw connector from impulse relay 
during following check. 




Injection time at different temperatures 
Tolerances: Injection time ±2 secs. Cut-out temperature 
±4“C (8°F) 



Hold injector above a suitable container. 

Run starter motor and observe injector. 

Fuel should be injected continuously when starter 
motor is cranked. Engagement time does however 
depend on engine temperature, see graph adjacent. 
Note! Some B 27 F engines may have been fitted with a 
thermal time switch with a 15°C (59°F) cut-out point. 
Incorrect injection time: remove connector from start 
injector. If injection is interrupted then thermal time 
switch is defective. If injection is still not interrupted, 
start injector is defective. 

Incorrect injection time: test with a new thermal time 
switch. 




25 




Group 23 Fuel system 
Cl-system, inspection 




Engines with impulse relay 



B7 

Check impulse relay 

Connect plug to relay. 

Hold start injector above a suitable container. 

Run starter motor and observe injectors. 

Fuel should be injected after approx. 1.5 secs, with 
subsequent injection for 0.1 secs. - pause 0.3 secs. - 
injection 0.1 secs. - pause 0.3 secs . . . 

Incorrect timing: test with a new impulse relay. 

No injection: defective relay or wiring. 







B8 ^ 

Start fuel pump 

Place hand on fuel filter to check that pump is operat- 
ing (filter vibrates slightly). 

1975-1977: Withdraw connector from air-flow sen- 
sor. 

1978-: Connect test relay 5170. 

Turn on ignition to start fuel pump. 

Fuel pump does not start: Check fuses, wires and 
relay. See Wiring diagrams on pages 83-85. 




26 






Group 23 Fuel system 
Cl-system, inspection 



Air-fuel control unit 

Operations B11-13 




r 

r 




B12 

Check plate position 

No part of plate may touch air venturi. Make sure that 
plate does not have any side play. 

Side play: recondition air-flow sensor. 

Incorrect position: loosen centre screw and adjust. 
Retighten screw. 

Height of sensor plate is checked later at max control 
pressure. 










B13 

Ensure that air-flow sensor plate does not jam 

Turn on ignition. 

Depress plate for a short while and listen to injectors. 



IMPORTANT! 8 27 E 1975-1978: sensor plate must be 
lifted. 



Note! Control pressure offers some resistance when 
depressing plate, do not mistake this for jamming. 

Injectors should only buzz when plate is depressed. 
On release, plate should return to rest position and 
buzzing should stop. 

Turn off ignition. 

Plate jams: recondition air-flow sensor. 

Injectors buzz with plate in rest position: control 
plunger in fuel distributor has jammed, clean/replace 
as required. Injectors do not buz2 with plate 
depressed: incorrect line pressure. 



27 






Group 23 Fuel system 
Cl-system, inspection 





Auxiliary air valve 



Operation B14 



B14 



Check that auxiliary air valve opens 

Valve should be partly open at room temperature and: 
Fully open at -30*C (-22*F) fully closed at +70°C 
(158®F). 



Use a penlight to Illuminate valve when checking 
operation. Replace valve if defective. 

Connect plug to valve. 

Closing operation of auxiliary air valve is checked at a 
later stage. 



Checking all pressures 



Operations B15-24 



B15 

Connect pressure gauge 5011 

Turn off ignition. 

Connect gauge between control pressure regulator 
and fuel distributor. 

Use hose 5116 and nipple 5032. 



Turn on ignition to start fuel pump 



B16 



B17 

Check line pressure 

Turn gauge cock on 5011 to position 1 (ie. towards fuel 
distributor). 

Record pressure when it is stable. 

Line pressure ■= 450-530 kPa (64-75 psi). 

Too low 




Too high 



Check control pressure (cold control pressure 
regulator) 

Turn off engine. 

Turn gauge cock on 5011 to position 2 (at right angles 
to hoses). 

Control pressure regulator should be at room tem- 
perature. 

Correct control pressures at different temperatures 
are shown in graphs on pages 29 and 30. 

Too low: test with a new control pressure regulator. 

Too high 











28 







Group 23 Cl system 




Cl-system, inspection 


Control pressure regulator . . . 004 


Control pressure regulator . . . 005 


B 27 F 1978 USA California + Japan 
1979 All markets 


B 27 E Early type 






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Control pressure regulator . . . 018 




Control pressure regulator . . . 029 


B 27 E Late type Sweden + Australia 




8 27 F 1977 USA 


B 27 F 1976 All markets 

1977 Japan + Canada 




1978 USA Federal + Canada 


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Group 23 Fuel system 
Cl-system, inspection 




Control pressure regulator . . . 021 

Altitude compensated. 

B 27 F Federal 1976 and 1977 some special versions. 
Tolerancesfor control pressure are ±25 kPa (± 3.6 psi). 
Diagram on left is based on air pressure at sea level 
and up to altitudes of approx. 600 meters (2000 ft) i.e. 
947 mbars or higher. For altitudes in excess of this it is 
necessary to know air pressure at time of test. 



B19 




kp/cm 2 kPa 



Check control pressure (warm control pressure 
regulator) 

Turn off engine. 

Connect plug to control pressure regulator. Regulator 
will now receive heating current and control pressure 
increases. 

After max. 5 minutes control pressure should increase 
to: 



Control valve pressure 

... 004 + ... 066 345-375 kPa (49-53 psi) 

.005 275-305 kPa (39-43 psi) 

. . . 018 + . . . 029+ . . . 38 . . 305-335 kPa (43-48 psi) 
Note I B 27 F USA Federal 1976 and 1977 with altitude 
compensated regulators: control pressure may vary 
depending on prevailing air pressure, see graph on 
left. 

Graph applies at sea level and up to 600 meters (2000 
ft) ie. 947 mbar or greater. 




Too high 




Control pressure, altitude compensated regulator 



30 




Group 23 Fuel system 
Cl-system, inspection 




B 27 E.B 28 E 
B 27 F 1976 all types 

1977 not California 

1978 USA Federal + Canada 



IMPORTANT! 8 27 F 1977 California: full load enrtch- 
mem system is not connected. 



B20 

Check enrichment at full load 

Check vacuum hose for leaks and make sure that it is 
correctly connected. 

Evacuate hose connected to control pressure regula- 
tor. Control pressure should increase. 



IMPORTANT! System must be evacuated carefully or 
regulator may be damaged. 



At a depression (vacuum) of 50 kPa (7 psi) control 
pressure should be 345-375 kPa (49-53 psi). 

Control pressure should return to the initial valve 
when pump is removed. 

Reconnect vacuum hose. 



Note! This test can also be performed with engine run- 
ning by comparing the gauge values with the vacuum 
hose connected and then disconnected. 



Thermostat valve 




B 28 F 



Operation B 21 on next page applies only for engines 
without a pressure differential switch. On engines with 
a pressure differential switch the acceleration enrich- 
ment system via the control pressure regulator must 
always be disconneted. 



31 









Group 23 Fuel system 
Cl-system, inspection 




B21 

Check acceleration enrichment 

B 28 F without pressure differential switch. 

Check vacuum hoses for leaks and correct connection. 
Disconnect hose from intake manifold and connect it 
to a vacuum pump. 

Evacuate system until pressure drops to approx. 50 
kPa (7 psi). 

Disconnect pump quickly and record control pressure 
on gauge 5011. Control pressure should drop to 145- 
175 kPa (21-26 psi) for one second and then return to 
the initial vslve. 

Reconnect hose to intake manifold. 

If incorrect: 

Check that delay valve is connected correctly, see fig., 
and that thermostat valve is open. 

Thermostat valve should be open at temperatures 
below 55®C (131*F). (Closing operation of valve is 
checked at a later stage.) 




B22 

Check rest pressure 

Turn gauge cock on 5011 to position 2 (at right angles 
to hoses). 

Turn off ignition. 

Record pressure when it is stable and for a further 
minute. 

Rest pressure = 150-240 kPa (21-34 psi). 

Pressure does not drop but is incorrect: adjust line 
and rest pressures, see page 47. 



Pressure drops 




B23 

Check pressure drop for 20 minutes 

Especially important if hot starting problems are en- 
countered. 

Pressure after 20 minutes should be at 150 kPa (21 psi). 
Too low 




32 






Group 23 Fuel system 
Cl-system, inspection 




B24 

Disconnect pressure gauge 5011 and nipples 
(hose) 

Turn off engine. 

Reconnect hose from control pressure regulator to 
fuel distributor. 



Air-flow sensor 

Operation B25 

B25 

Check air-flow sensor plate rest position 

Fuel pump must be operating for this test and con- 
trol pressure at max, value. 




B 27 E 1975-1978 
Turn on ignition. 

Upper edge of plate should lie flush or at most 0.3 mm 
(0.012 in) below cylindrical part of air venturi, see fig. 
Turn off Ignition. 

Incorrect position: adjust by bending/straightening 
spring beneath plate. 



Other models 
Turn on ignition. 

Upper edge of plate should lie flush or at most 0.3 
mm (0.012 In) above cylindrical part of air centuri, 
see fig. 

Turn off ignition. 

Incorrect position: adjust by tapping pin upwards/ 
downwards. It Is necessary to remove upper part of 
air-flow sensor to obtain access to pin. 






Group 23 Fuel system 
Cl-system, inspection 







Auxiliary air valve 

Operation B26 

B26 

Check that auxiliary air-valve closes 

Turn on ignition. 

Valve should be completely closed after approx. 5 
minutes at 20*C (68°F). 

Turn off ignition. 

Does not close: tap lightly on valve. If it closes now it is 
not defective {engine vibrations usually cause valve to 
close). 



II does not close 






Injectors 
Fuel distributor 

Operations B27-40 







B27 

Remove injectors from cylinder heads 



B28 



Make sure that fuel distributor does not leak 
internally 

Turn on ignition to start fuel pump. 

Observe injectors, they may become moist but 
must not start to drip. 

Turn off ignition. 



Injectors drip: internal leakage in fuel distributor. 
Replace. 




B29 

Check injectors for leakage at rest pressure 

Depress* sensor plate until slits in control plunger 
are open and observe injectors. 

| * B 27 E 1976-1978: sensor plate must be lifted. | 

Injectors may become moist but must not drip in a 
15 second period. 

One or more injectors leak: clean injectors and 
test with test apparatus described on page 74. 



34 






r 




Group 23 Fuel system 

Cl-system, inspection 
B30 

Check difference between fuel delivered from 
each injector 



This test should only be carried out in cases of obvious 
engine malfunction. Otherwise continue with opera- 
tion B40 on page 38. 



There are two types of measuring equipment in use: 

- meter 0976 (USA + Canada), see operation B34 on 
page 36. 

- fuel metering unit 5014, see operation B31 below. 





Fuel metering unit 5014 
Operations B31-33 

B31 

Connect fuel metering unit 5014 

To obtain correct readings all hoses should be either 
empty or full at start of test. 



B32 

Check fuel deviation 

Turn on ignition to start fuel pump. 

Depress* sensor plate halfway. Keep it depressed in 
this position until 100 cm 3 of fuel is collected in one of 
measuring cylinders. Then release plate. 

| * B 27 E 1975-1978 sensor plate must be lifted. 

Injectors should start delivering fuel at same time. 
Max fuel deviation must not exceed 20%. 

Turn off ignition. 



Greater than 20%: repeat test to be exactly sure. 

If deviation is still greater than 20%, swap hoses be- 
tween two injectors (one correct and one faulty) and 
repeat test. 

If results are still same, injector or hose is defective. 
Clean injector and test in test equipment described on 
page 74. 

If other injector malfunctions, fuel distributor is defec- 
tive and will have to be replaced. 



35 




Disconnect fuel metering unit 

Pour fuel back into tank. 



B33 




Proceed to 




Test meter 0976 
Operations B34-40 
USA and Canada only 



Note! Fuel pump must be running during test. A battery 
charger (max. charge 15AI can be connected to prevent 
battery from discharging. 

Low battery voltage will decrease fuel pump capacity 
and test results will be invalid. 



B34 



Connect meter 0976 

Support meter on a flat surface, next to car, and make 
sure that it is horizontal by checking built-in spirit 
(bubble} level. 

Connect injectors to hoses from meter, injector No. 1 
to hose No. 1 etc. 

Insert meter return line in fuel tank. 



B35 

Evacuate meter and lines 

Turn on ignition. 

Depress air-flow sensor plate to its max. position. In- 
sert tool 0977 so that plate does not move. 



Depress meter switches one at a time, and open meter 
knob. Continue until both tubes in meter are evacuat- 
ed and free from air bubbles. 

Remove 0977 and release air-flow sensor plate. 





G roup 23 Fuel system 
Cl-system, inspection 



r 




B36 

Check fuel flow at idle position 

Turn meter knob to left (white spot). 

Depress switch for injector No. 1. Depress air-flow 
sensor plate until a flow of approx. 6 cm 3 /min is ob- 
tained. Keep plate in this position with tool 0977. 
Depress switches for remaining injectors one at a time 
in order to find out which injector has lowest fuel flow. 
Depress switch for injector with lowest flow. Position 
tool 0977 so that flow becomes 6.0, 6.6 or 7.2 cmVmin. 
Check fuel flow for remaining injectors. Flow values 
for remaining Injectors can only lie above set value. 



Set value 

6.0 crr^/min 
6.6 " 

7.2 " 



Max permissible fuel flow 

7.2 cm*/min 
7.9 " 

8.6 " 




Incorrect fuel flow: 

Turn off ignition. 

At fuel distributor, swap a fuel line (with incorrect 
flow) with a fuel line having a correct flow. 

Repeat flow test. 

If fault still remains on same injector, either the injec- 
tor or fuel line is defective. Clean injector and test in 
test apparatus described on page 74. 

If fault moves to other injector, fuel distributor is de- 
fective and will have to be replaced. 







B37 

Check fuel flow at part load 

Turn meter knob to right (white spot). 

Position tool 0977 so that fuel flow for injector with 
lowest flow becomes 40, 50 or 60 cm J /min. 

Check fuel flow for remaining injectors. 

Set fuel flow Max permissible 

40 cm 3 /min 46 cm 3 /min 

50 " 57 ” 

60 » 68 " 

Incorrect fuel flow: Turn off ignition. Swap fuel lines at 
fuel distributor. Repeat test as previously described. 



37 





Group 23 Fuel system 
Cl-system, inspection 




Check fuel flow at full load 



Turn meter knob to right. 

Depress sensor plate to its max position. Check which 
injector has lowest fuel flow. Place tool 0977 so that 
flow for this injector becomes 120 or 140 or 160 
cm’/min. Select as high a value as possible. 



Check fuel flow for remaining injectors. 



Set fuel flow 

120 cm 3 /min 
140 
160 " 



Max. permissible fuel flow 

131 cmtymin 
153 " 

175 ” 



Incorrect fuel flow: Turn off ignition. Swap fuel lines at 
fuel distributor. Repeat test as previously described. 




H 




B41 

Reconnect wiring and plugs 

Plug in connector to ignition system control unit. 

IMPORTANT! Ensure rubber seal in connector is instal- 
led correctly. Without it water can enter and cause cor- 
rosion, poor contacts etc. 

1975-1977: plug in air-flow sensor connector. 

1978-: disconnect test relay 5170. Reconnect wire to 
ignition coil. 



38 






Group 23 Fuel system 
Cl-system, inspection 




B42 



Check/adjust throttle cable 

Throttle pulley should strike stop at idle position. Ca- 
ble should be taut but should not move pulley. Adjust 
using cable sleeve. 

At full throttle, pulley should strike other stop. 










B43 

Check/adjust kick-down cable (auto) 

Depress accelerator to floor. 

IMPORTANT! Do not adjust throttle by hand otherwise 
setting will be incorrect. 

At full throttle distance from cable sleeve to clip 
should be 50.4-52.6 mm (1.98-2.07 in). 

Adjust using cable sleeve. 




End of inspection 







Group 23 Fuel system 
Cl-system, inspection 



Different faults discovered during inspection 

Operations B46-63 




From B6: No fuel injected from start 
injector 

When fault has been rectified proceed from B7 



B46 

Check for voltage at start injector when starter 
motor is operating 

Measure voltage across both pins. 

Voltage: test using a new start injector. 




B47 

Check for voltage between plug and ground 
when starter motor is operating 
Voltage: indicates a defective thermal time switch or 
an open circuit in the lead between it and the start 
injector. 

No voltage: open circuit in lead between starter motor 
and start injector. 



End 



40 



Group 23 Fuel system 
Cl-system, inspection 



From B17: Line pressure too low 

When the fault has been rectified proceed from 
B18 



r 



r 




648 

Fuel leakage? 

Check for fuel leakage between fuel pump and fuel 
distributor. 

Cars equipped with a fuel leakage return line between 
fuel accumulator and fuel tank: remove tank cap to 
release overpressure from fuel system and disconnect 
hose from fuel accumulator. Check that fuel accumula- 
tor does not leak. Reconnect hose. 




B49 



Check tank pump 



Tank pump was introduced in 1977 but may have been 
fitted to some models before this. 



Unscrew fuel tank cap and listen for sound of pump. 
A defective tank pump often causes a noisy main fuel 
pump. 

Tank pump does not work: check fuse in boot/trunk 
(1975-1978) or fuse No. 5 in fusebox (1979^). 



r k 




B50 

Check tank pump current consumption 

Connect an ammeter as illustrated. 

Current should be 1-2A. 

Incorrect: Check tank pump and filter for blockages. If 
correct, retest with a new tank pump. 

No current: Check for voltage at pump. If correct test 
with a new pump. 



41 







Group 23 Fuel system 
Cl-system, inspection 




B51 

Check fuel pump capacity 

Turn off ignition. 

Unscrew fuel tank cap to release overpressure from 
fuel system. 

Disconnect return line at connection in engine com- 
partment 8nd hold end above a measuring cylinder. 
Turn on ignition for 30 seconds. 

Min. volume of fuel should be: 



1975-1979 0.8 litres (0.75 US qts) 

1980- 1.0 litres (1.0 US qts) 



Reconnect return line. 

Incorrect pump capacity: Retest with a new fuel 
pump. If this does not help, fault may be due to a 
blocked fuel filter, fuel line or fuel distributor. 




42 







Group 23 Fuel system 
Cl-system, inspection 



From B17: Line pressure too high 

When the fault has been rectified proceed with B18 




B53 

Check that return line is not blocked 

Turn off ignition. 

Unscrew fuel tank cap to release overpressure. 
Disconnect return line from fuel distributor and blow 
through line. 

Blocked line: clean/replace. 

OK: check that fuel fitting screw holes are not blocked. 
Reconnect return line. 



654 

Adjust line and rest pressures 

See page 47. Check line pressure regulator and check/ 
replace O-rings. 



End 




From B18 and B19: Control pressure 
too high (cold/warm control 
pressure regulator) 

When the fault has been rectified proceed with B19 
(B20) 

855 

Check that return line is not blocked 

Turn off ignition. 

Unscrew fuel tank cap to release overpressure. 
Disconnect return line from control pressure regula- 
tor. 1978- : also disconnect line from fuel distributor. 
Blow through line. 

Blocked line: clean/replace. 

OK: check that fuel fitting screw holes are not blocked. 
Retest with a new control pressure regulator. 

Note! 1978-: fault may be due to a blocked line 
pressure regulator. 



End 



43 








Group 23 Fuel system 
Cl-system, inspection 



From B19: Control pressure too low 
(warm control pressure regulator) 

When the fault has been rectified proceed with 
B20 




B56 

Check for voltage at control pressure regulator 

Connect a test lamp across plug pins. Lamp should 
light. 

Lamp lights: measure regulator resistance. Resis- 
tance varies with type of regulator. 

Control pressure regulator (last 3 digits of identifica- 



tion number) Resistance 

005+018+029 + 038 20-24 n 

004+021 20-30 n 

066 at temperatures below 12°C 54°F 32-38 fl 



above 18®C (64°F) . 16.5-19.5 ft 
If resistance is correct, fault is due to a poor contact 
between plug and regulator. 



Lamp does not light: proceed to B57. 





IM77S 



B57 

Check for voltage between plug and ground 
Voltage: open circuit in lead to ground. 

No voltage: open circuit in lead between pump relay 
and control pressure regulator. 









l End I 








Group 23 Fuel system 
Cl-system, inspection 




From B22 and B23: Rest pressure 
drops 

When the fault has been rectified proceed with 
B23 ( B24 ) 

B58 

Check rest pressure. Gauge cock in position 1 

Turn on ignition to build up pressure in fuel system. 
Turn off ignition. 

Turn gauge cock on 501T to position 1 (towards fuel 
distributor). 

Wait and record pressure after 5 minutes, (this is 
necessary because fuel accumulator compensates for 
any leakage as long as it contains fuel under pressure). 

Pressure does not drop in position 1 : fault is due to one 
or more of the following: 

- fuel line leak 

- 1975-1977: fuel flow through control pressure 
regulator too great. Test with a new regulator. 

- 1978- : needle valve in line pressure regulator does 
not close. Clean/replace needle valve and fitting. 




B59 

Fuel leakage? Check for fuel leakage between 
fuel pump and fuel distributor 

Cars equipped with a fuel leakage return line between 
fuel accumulator and fuel tank: remove tank cap to 
release overpressure from fuel system and disconnect 
hose from fuel accumulator. Check that fuel accumula- 
tor does not leak. 

Reconnect hose. 



B60 

Make sure that line pressure regulator does not 
leak 

Unscrew fuel tank cap to release overpressure. 
Switch on ignition to build up pressure in fuel system. 
Switch off ignition. 

Disconnect return line (junction nextto filter) and hold 
end of hose up. If fuel flows out of hose, line pressure 
regulator is leaking. 

Reconnect return line. 

Line pressure regulator leaking : Replace O-ring. If this 
does not help, replace fuel distributor. 



45 








Group 23 Fuel system 
Cl-system, inspection 




B61 

Check fuel pump non-return valve 

Switch on ignition to build up pressure in fuel system. 
Switch off ignition. 

Block line between tank pump and fuel pump using 
pliers 2901. 

Record rest pressure for 5 minutes. 

Rest pressure drops: start injector or line to it, leaking. 
Rest pressure does not drop: non-return valve is leak- 
ing, replace. 



End 




From B26: Auxiliary air valve does 
not close 

When the fault has been rectified proceed with 
B27 



B62 

Check for voltage at auxiliary air valve 

Connect a test lamp across pins. Lamp should light. 
Lamp does not light: check ground connections. Con- 
nect lamp across yellow wire (1975) or blue wire 
(1976—) and ground. 






B63 

Check auxiliary air valve resistance 

Connect an ohmmeter across auxiliary air valve plug. 
Model year Resistance 

1975-1979 15-21 ft 

1980-1983 40-60 ft 

Correct: indicates poor plug contact. 

Incorrect: replace auxiliary air valve. 



End 



46 







Group 23 Fuel system 

Cl-system, adjusting pressures 



Adjusting line and rest pressures 



r 




Add or remove shims from line pressure regulator as 
required. 

Line and rest pressures are effected to a similar extent 
by shims. Both increase by addition of shims and vice- 
versa. 



Shims are available in following thicknesses: 

Thickness Pressure change 

1976-1977 0.1 mm 6 kPa (0.85 psi) 

0.5 mm 30 kPa (4.3 psi) 



1978- 0.1 mm 15 kPa (2.13 psi) 

0.15 mm 22 kPa (3.2 psi) 

0.6 mm 90kPa(13psi) 



Line pressure 450-530 kPa 

(64-75 psi) 

Rest pressure 150-240 kPa 

(21-34 psi) 



r 

c- 



47 






Group 23 Cl system 
Cl- system, Fault tracing 



C. Fault tracing. Cl system 




123 764 



Cl 



General 



The instructions in this section apply only if the engine 
is free from any mechanical orelectrical faults. Correct 
octane fuel supplied by well known companies must 
be used. 



The following points should always be checked before 
following the fault tracing procedures. 



Mechanical 



Electrical 



Emission controls 



- compression 

- valve clearances 

- vacuum hoses and connections 

- throttle control, kick-down control 
(auto gearbox) 

- air cleaner 

- intake manifold (leakage). 

- exhaust system (leakage). 



- spark plugs and HT leads. 

- distributor cap 

- ignition coil 

- timing (incl. ignition advance) 

- all electrical connections. 

- constant idle speed system (CIS) 



- crankcase ventilation 

- exhaust gas recirculation 
(EGR) 

- evaporate control 
system 

- airpump/Pulsair system 

- Lambda-sond system 

- catalytic converter 





C2 



Description: 

Only the most common and easily detected fault 
symptoms are included in this section. 

Perform a complete inspection of the Cl system (see 
page 24): 

- if no faults are found when fault tracing 

- if no easily detected symptoms are found 

- if several components malfunction. 



The fold-out section overleaf contains a list of the 
most common symptoms and related checks. 

The letter and number (e.g. B2) after each check refer 
to operations in the 'Inspection of the Cl system". 
Refer also to the wiring diagram on pages 83-85. 



48 





Group 23 Cl system 
Cl-system, Fault tracing 



Fault symptoms and causes 
Symptoms, probable faults/remedies 

Fold out this section while performing the fault tracing procedures. 




Group 23 Cl system 
Fault tracing 



FAULT SYMPTOM 


CAUSE 


Engine does not start 


Cold engine difficult to start 


| [ Hot engine difficult to start 


1 


Erratic running, cold + during warming-up 




Erratic running, hot 


| Erratic idle 


4' 


Occasional stalling 


L 


ow top speed, poor performance 

Excessive fuel consumption 
l 


* 


Leakage, fuel/air 

Inlet system, air leakage 
Fuel system, external leakage 
Fuel distributor, leakage 
Air leakage, injector holder 


XXX 

X 

X 


X 


X 

X 


X 


X 

X 


X 

X X 

X 

X 

X 

X 


X 

X 


X 

X 


. 

X 

X 


X 

X 

X 


Pressure (line, control and rest) 

One or more of the pressures incorrect 
Line pressure incorrect 
Control pressure, cold, too high 
Control pressure, cold, too low 
Control pressure, warm, too high 
Control pressure, warm, too low 

Control pressure, B28F: acceleration enrichment, cold engine defective 
Control pressure, B27E, B28E, B27F 1976-78 full load enrichment defective 
Rest pressure, too low (vapour locks) 

Rest pressure, too high (injectors leaking) 


X 

X X 


X 


X 


X 

X 




Fuel pump, tank pump 

Fuel pump does not start (relay, fuses) 

Fuel pump, low capacity, poor connections 
Tank pump faulty 


XXX 

XXX 


x > 


X 

X 


X 

X 


X 


Air-fuel control unit 
Air flow sensor plate, incorrect position 
Sensor plate-lever-control plunger jamming 
Fuel distributor blocked 


X X 
X 

X 

XXX 


x > 


C X 


X 




Start injector 
Does not open 

Thermal timer switch shorted 
Impulse relay defect 
Does not close 


XXX 


x > 


( X ) 


< X 




Lines, filters 

Fuel lines/filters for tank pump, blocked 


X 




X 


X 




Auxiliary air valve, injectors 

Auxiliary air valve, does not open 
Auxiliary air valve does not close (fast idle) 
Injectors blocked (fuel not atomized) 
Injectors leaking 


X 


x > 


C X ) 
X ) 
X 


( X 
X 


X 


CO, throttle valve, controls 

CO content, incorrect 
Throttle valve, loose 
Throttle valve incorrectly set 



49 




Group 23 Cl system 
Cl-system, Fault tracing 



Engine does not start 



Probable cause 


Operation 


Air inlet system, leakage 

Fuel pump, defective 

Air-fuel control unit (control plunger) 

seizes 

Incorrect pressure 
Sensor plate height, incorrect 


B1, 4 
B2, 8 

B11-13 

B15-24 

B25 


Cold engine difficult to start 


Probable cause 


Operation 


Start injector, defective 
Auxiliary air valve, defective 


B3, 5-6 
B14 


Hot engine difficult to start 


Probable cause 


Operation 


Impulse relay, defective 
Start injector leaking 
Rest pressure too low 


B5-7 
B2, 8-10 
B15-16, 
22-23 


Engine difficult to start cold + hot 


Probable cause 


Operation 


Air inlet system, leakage 
Start injector, impulse, 
relay defective 

Sensor plate position, incorrect 
Line pressure, incorrect 
Sensor plate height, incorrect 


B1, 4 

B2, 5-7 
B11-12 
88, 15-17 
824-25 



Erratic running, cold + during 
warming-up 



Probable cause 


Operation 


Control pressure, cold, incorrect 

Acceleration enrichment, 
cold engine, defective 8 28 F 


B2-3, 8 
B 15-16, 18 

B19, 21 



Erratic running, cold + hot engine 



Probable cause 


Operation 


Air inlet system, leakage 
Control pressure, incorrect 

CO content, incorrect 
Throttle valve, loose 


B1, 4 

B2, 8, 15-16, 
18-20 



Erratic running + excessive fuel 
consumption 



Probable cause 


Operation 


Start injector leakage 
Control pressure, incorrect 

CO content, incorrect 


B2-3, 5.8-10 

B15-16, 

B18-20 



Low top speed + poor performance 



Probable cause 


Operation 


Throttle control setting, 
incorrect, throttle valve does 
not open fully 
Incorrect control pressure 
when engine warm 
Tank pump, defective 
Fuel pump capacity, too low 
CO content, incorrect 


B2, 8, 15-16, 
18-21 
B49-50 
851 



Erratic idle 



Probable cause 


Operation 


Engine does not run on all cylinders 
Air inlet system, leakage 
Air-fuel control unit seizes 
Throttle valve, loose 
Injectors leaking, poor spray pattern 


81,4 

B2,8, 11-13 
B27-40 



Erratic running, hot engine 



Probable cause 


Operation 


Control pressure warm, incorrect 


B2, 8, 15-16, 
19-20 





Group 23 Fuel system 
Tank pump 



D. Cl-system, components, checking, replacement etc 



TANK PUMP 



Operations D1-D10 




01 

General 

Tank pump was introduced into production in 1977, 
but may have been fitted to vehicles manufactured 
before this. 



D2 



Fault symptoms 

A defective tank pump may cause low line pressure. 
The following symptoms can arise: 

- noisy main fuel pump 

- low top speed, poor performance 

- juddering, engine cut-out (fuel vapour locks!. 





03 

Check tank pump 

Carry out operations B2, B8, B49-50. 



D4 

Tank gauge unit, removing/installing 

(necessary if tank pump or filter is to be replaced). 
Unscrew fuel tank cap to release overpressure from 
fuel system. 

Remove/install tank gauge unit through aperture in 
rear floor section. 

Use tool 5169. 

Install new O-ring smeared with glycerine or similar. 

There are three different types of tank gauge units in 
use, see pages 51-S3. 

Note! Type 2 or 3 units may have been fitted to early 
production vehicles if fuel tank has been replaced. 



50 





Replacement of tank pump/filter: 

- locate upper clip as shown, otherwise it will be 
difficult to fit unit in tank 

- route earth/ground lead under hose clips. If this is 
not done movement of float will be inhibited. Do not 
stretch earth/ground lead 

- return hose must be fitted on vehicles equipped with 
parking heaters 

- check that filter does not interfere with movement of 



Wiring diagram 

A = wiring harness Colour codes 
B = tank pump GR = grey 

C = suppressor Y = yellow 

D - fuse SB = black 

E - fuel pump BR = brown 







Croup 23 Fuel system 


& 




Tank pump 

Type 1 

Operations D5-6 

Applies to models from 1975-1976 and early part of 



E 



51 






Group 23 Fuel system 



Tank pump 



Operations D7-8 
1977-1978 



Without plug 



Replacement of tank pump/filter: 

- connect leads to the pump 

- check height, see left, adjust if necessary 

- check that filter does not contact float. 



Wiring diagram 

A = wiring harness Colour codes 
B - tank pump GR = grey 

C = suppressor Y = yellow 

D = fuse SB = black 

E - fuel pump BR - brown 






Group 23 Fuel system 
Tank pump 



Type 3 

Operations D9-10 
1978-1983 









AC 



D9 

Replacement of tank pump/filter: 

- connect leads (earth/ground junction! to pump 

- check that filter does not contact float. 

Note! 1978-1981 models may be fitted with pumps 
from two different manufacturers. AC and VDO. Only 
the AC pump is stocked, the two pumps are however 
interchangeable. 

If a suppressor has not been fitted to the fuel level 
sensor unit a separate suppressor must be fitted when 
changing from VDO to AC pumps. See next page. 



53 





Group 23 Fuel system 
Tank pump 




DIO 

Parts required when changing from VDO to AC 
tank pump 

Part P/N Qty 

1 - pump 1276330-6 1 

2- bracket 1235444-5 1 

3 - nut 1266390-2 2 

4- washer 940121-7 2 

If necessary 

5 - suppressor 1235204-3 1 

6 - plug insulator 958207-3 1 

7 - sleeve insulator 958208-1 1 



8 - filter 



1266822-4 1 



The earth/ground strap (9) must be transferred to the 
new pump, and where applicable the suppressor must 
be connected in series with the positive terminal of the 
pump. 










54 




Group 23 Fuel system 
Fuel pump, fuel accumulator 



FUEL PUMP WITH NON-RETURN (CHECK) VALVE 
FUEL ACCUMULATOR 

Operations D11-18 



1975-1977 




Dll 



Fault symptoms 

Fuel pump: a faulty fuel pump will cause low line 
pressure. The following symptoms may arise: 

- engine difficult to start or does not start 

- engine misfires during driving, under heavy load 

- poor acceleration 

- engine starts but stops immediately 

- poor engine performance 

- pump noise. Notel May also be due to a defective 
tank pump or vapour locks in the fuel system. 

Fuel pump non-return valve, fuel accumulator: if 
these components are defective, the rest pressure will 
be below the specified value. 



Symptoms: 

- difficult to start warm engine. 



1978-1983 




D12 

Inspection 
Fuel pump 

Record the pressure. Carry out the following opera- 
tions B2, 8. 15-17. 

Fuel pump non-return valve/fuel accumulator 

Measure the rest pressure. Carry out the following 
operations B2, 8, 15-17, 22-23. 



073 



Replacement 

Fuel pump: never fit an old non-return valve to a new 
pump (a new non-return valve and seal is supplied 
with the new pump). 



On replacing the pump, check that all pressures are 
correct, check also the idle speed and CO content. 



Fuel pump non-return valve or fuel accumulator: 

check the rest pressure after replacement. 




Group 23 Fuel system 

Fuel pump, fuel accumulator 



Fuel pump, fuel accumulator 1975-1977 without tank pump 

Operations D14-15 




56 





Group 23 Fuel system 



Fuel pump, fuel accumulator 



Connecting fuel line to pump (non-return valve) 
1978-1979: 

- connect hose by hand 

- hold the pump (pump must not be supported on a 
bench otherwise it may be damaged) 

- carefully tap in hose. Use a clean hammer. 



D18 

Replacement of fuel pump/non-return valve 
1980-1983 

A ground, bevelled, 17 mm open-ended spanner 
(wrench) is needed for this operation. 



Remove pump, fuel accumulator and bracket in one 
unit. 

Use open-ended spanner described above to coun- 
terhold pump when disconnecting fuel line. Take care 
not to damage electrical connections on pump. 



Use a long 17 mm socket spanner (wrench) to remove/ 
install non-return valve. 



Group 23 Fuel system 
Fuel filter 



FUEL FILTER 

Operations D19-21 




D19 



Fault symptoms 

A blocked fuel filter causes line pressure to drop 
(reduced fuel supply). This can cause: 

- difficult to start engine 

- misfiring while driving under heavy loads 

- erratic acceleration 

- poor performance 



Fuel filter USA 1980-, other markets 1981- 



D20 

Checking fuel filter 

Measure line pressure. Perform following operations 
B2. 8, 15-17. 




maos 



USA - 1979, other markets - 1980 

For ecnomical reasons, only one type of fuel filter 
(P/N 1276050-0) is stocked by the Parts Department. 
When replacing a fuel filter with the above filter, addi- 
tional nipples and seals are required. 



D21 



Replacement of fuel filter: 

- turn nipples so that tapered side faces outwards, 
away from filter 

- note flow indicating arrows on filter. 



Example: When replacing a fuel filter marked . . . 006, 
an additional nipple (P/N 1276068-2) and a seal (P/N 
947621-9) are required. 








Croup 23 Fuel system 
Air-fuel control unit 



AIR-FUEL CONTROL UNIT 

Operations 022-65 




B27E 1979-1980. B28E. B 27/28 F 



022 

Fault symptoms 

A defective air-fuel control unit can cause: 

- difficult to start engine 

- erratic operation 

- erratic acceleration 

- excessive fuel consumption 

- variable CO-content 

- dieselling (running-on). 



023 

Checking air-fuel control unit 

A thorough inspection of Cl-system should be carried 
out before replacing/reconditioning the air-fuel con- 
trol unit (air-flow sensor of fuel distributor). See page 
24. 



D24 

Type of air-fuel control unit 

Two main types of air-fuel control unit are in use: 

Page 



B 27 E 1975-1978 removing 62 

installing 62 

reconditioning 64 

Other models, removing 68 

installing 68 

reconditioning 70 



61 




Group 23 Fuel system 
Air-fuel control unit 



B 27 E 1975-1978 




Removing air-fuel control unit 

Operations D25-27 

D25 

Remove air-fuel control unit with intake 
manifold 

First unscrew fuel tank cap to release overpressure 
from fuel system (reduces spillages). 

Clean all connections carefully before disconnecting 
fuel lines. 



D26 

Detach air-fuel control unit from intake 
manifold 



D27 

Disconnect fuel lines 

Clean all connections thoroughly before disconnect- 
ing fuel lines. 




Installing air-fuel control unit 

Operations D28-33 
Special tools: 5102, 5170 1 1978 ) 



D28 

Connect fuel lines 

Install new seals. 

It is important that fuel lines are routed as shown 
adjacent. Fuel lines for injectors 2, 3, 5 and 6 are of 
same length. 



1HM45 



62 





Croup 23 Fuel system 

Air-fuel control unit 
029 

Attach air-fuel control unit to intake manifold 
IMPORTANT! There are two types of fuel lines, one 
with a rubber sleeve and one without. 

Fuel lines with rubber sleeves: check to see that a 
bracket (P/N 1269051/71 (see below) has been fitted to 
prevent fuel lines from interfering with throttle con- 
trol. This bracket must not be used for other type fuel 
lines. 



D30 

Install intake manifold with air-fuel control unit 

Connect all fuel lines. 






031 

Start fuel pump 

Disconnect plug from ignition system control unit. 
1975-1977: withdraw plug from air-flow sensor. 

1978- : connect test relay 5170. 

Turn on ignition. 



032 

Basic-set air-fuel control unit (CO adjustment 
screw) 

Disconnect fuel line from fuel distributor. 

Turn CO screw clockwise until fuel is supplied from 
outlet. Then tighten screw by half a turn, using wrench 
5102. 

Turn off ignition and reconnect fuel lines. 



033 



Check/adjust: 



Operation 

- all pressures B3, 15-24 

- rest position of air-flow sensor plate . B25 

- idle speed and CO-content J3-7 



63 



Group 23 Fuel system 
Air-fuel control unit 



Reconditioning air fuel control unit 

Operations D34-46 




Remove fuel distributor 



D34 



Take care that control plunger does not fall out as it is 
easily damaged. 

If control plunger is removed, it must be cleaned in 
clean petrol/gasoline before being refitted. 



D35 

Remove lower part of air-flow sensor 

Allen key 5 mm. 







64 



Group 23 Fuel system 
Air-fuel control unit 




D37 

Reinstall lever + plate and adjustment arm 

Grease bearing surfaces, shaft, balls and spring. 




D38 



Reinstall counterbalance 

Centre lever before tightening retaining screws for 
counterbalance. 

CO adjustment screw should be opposite drilled hole 
in housing. Key/wrench 5015 can be used to check 
this. 




65 



Group 23 Cl system 
Air-fuel control unit 




D41 

Check operation of sensor plate/lever 

Check throughout complete travel that plate does not 
stick, and is easy to move. 





a r 

• f - * 0-Q3mm 


o 


~yi 






D42 

Adjust plate rest position 

Upper edge of plate should be flush, or at the most 0.3 
mm (0.012 in) below cylindrical part of air venturi. 
Position can be adjusted by bending/straightening 
spring clamp beneath plate. 



Note! The rest position of the sensor plate should be 
checked before fitting the air-fuel control unit. It is ad- 
visable to set the plate as near flush as possible. This is 
because the plate takes up a low rest position when the 
unit is installed and is affected by the control pressure. 



Fuel distributor 



The fuel distributor must not be disassembled. If any 
part is defective, the complete unit must be replaced. It 
is however possible to clean the control plunger. The 
line pressure regulator can also be cleaned. O-rings 
seals should be replaced. 




D43 

Clean and check control plunger 

Always use clean petrol/gasoline and observe utmost 
cleanliness. 

Wash control plunger and blow clean with com- 
pressed air. Also clean metering slits. 

Make sure that plunger is not damaged or coated with 
carbon deposits. Use finger nails to remove dirt par- 
ticles. on no account may tools be used. 

Refit plunger in fuel distributor and check in-out 
operation, turning at same time. Plunger should move 
freely, if not replace complete fuel distributor. 



66 









Group 23 Fuel system 



Air-fuel control unit 



Clean and inspect line pressure regulator 

Use clean gasoline/petrol and observe the utmost 
cleanliness. 

Disassemble and clean regulator. 

Replace worn and damaged parts. 

IMPORTANT! Piston must not be replaced separately. 
If piston is defective the complete fuel distributor 
must be replaced. 

Reassemble and install regulator, using new O-rings 
and seals. 



1975-1977 










fi i| r 

jjjjL 




L 


1 V 


WJ17 



D45 

Install fuel distributor on air-fuel sensor 

Install new O-ring and make sure that it sits correctly. 
Take care that control plunger does not fall out. If 
damaged it must be replaced. 

Tighten screws evenly. Tightening torque 3.6 Nm (2.6 
ft lbs). 




D46 

Assemble upper and lower parts of air-flow sen- 
sor 

Install new seal. 

Allen key 5 mm. 

Check after tightening that lever moves freely. 



67 



Group 23 Fuel system 
Air-fuel control unit 



B 27 E 1979-1980: B 28 E: B 27 F: B 28 F 




Removing air-fuel control unit 



047 

Remove upper section of air-flow sensor along 
with fuel distributor 

Note! If necessary, fuel distributor can be removed 
and checked separately. 

Unscrew fuel tank cap to release overpressure from 
fuel system (reduces spillages). 

Clean all connections thoroughly before disconnect- 
ing fuel lines. 

Allen key 5 mm. 






Installing air-fuel control unit 

Operations D43-52 

Special tools: 5102, 5170 (1978-) 





D49 

Install air-fuel control unit 

Install new seal. Allen key 5 mm. 

Check after tightening that air-flow sensor plate 
moves freely. 

Connect all fuel lines apart from one. Use new seals. 



68 




Group 23 Fuel system 
Air-fuel control unit 





DSO 

Start fuel pump 

Disconnect plug from ignition system control unit. 
1975-1977: withdraw connector from air-flow sensor. 
1978- : connect test relay 5170. 

Turn on ignition. 




D51 

Basic-set air-fuel control unit CO-adjustment 
screw 

Disconnect fuel line from fuel distributor. Turn CO 
screw clockwise until fuel is supplied from outlet. 
Then tighten screw by half a turn, using wrench 5102. 
Turn off ignition and reconnect fuel line. 



D52 

Check/adjust: 



Operation 

- all pressures 83, 15-24 

- air flow sensor plate rest position . . . B25 

- idle speed and CO-content 

B 27 E 1979-1980 J8-15 

B 28 E J8-15 

B 27 F J16-30 

B 28 F J16-30 





Group 23 Fuel system 
Air-fuel control unit 




Reconditioning air-fuel control unit 

Operations D53-65 



D53 



Remove fuel distributor 

This should be done carefully to prevent control 
plunger from falling out and becoming damaged. 

A control plunger which has been removed must al- 
ways be cleaned in clean gasoline before reinstalling. 




D54 

Remove lever and adjustment arm 

Slacken clamping screws, lever -shaft. 

Remove snap-rings, cover washers, O-rings, spring 
(one side) and balls. It may be necessary to tap lightly 
on side to free balls. 

Press out shaft and lift out lever and adjustment arm. 



D55 

Clean and inspect all parts 

Replace worn or damaged parts. 

Make sure that spring and pin (for adjusting height of 
sensor plate) are not loose. 

1976-1977: Check connector on air flow sensor. 



USA 1981-1982: Canada 1982 

D56 

Remove seal (steel ball) from air flow sensor 

3 mm drift (0.125 in). 



057 

Assemble lever and adjustment arm 

Install counterbalance (if removed). 

Place adjustment arm in lever. 

If sensor plate has been removed: plate should be 
positioned so that bevelled edge faces lever. 






'S 



70 




Croup 23 Fuel system 
Air-fuel control unit 




D58 

Assemble air flow sensor 

Grease bearing seats, shaft, balls and spring. 

Place lever and adjustment arm in air flow sensor and 
press in shaft. Note! Hold adjustment arm straight 
when shaft is pressed into position, otherwise shaft 
will not be free to turn. 

Install balls, spring, O-rings, cover washers and 
circlips. Spring should be installed in side where bear- 
ing seat is deepest. 



D59 

Align lever 

CO adjustment screw should lie directly in front of 
hole in housing. Use key 5102 to check. 

Tighten clamping screws, lever - shaft. 




Center sensor plate 

Adjust to obtain equal clearance all around. Unscrew 
center bolt when adjusting plate. 



D61 

Check operation of sensor plate/lever 

Parts should move easily and without binding. 




D62 

Adjust sensor plate rest position 



Notel it is advisable to set sensor plate slightly above 
flush position. This is because when unit is installed it is 
only possible to tap pin downwards i.e. lower position 
of plate. 



Upper edge of plate should lie flush, or at the most 0.3 
mm (0.012 in) above cylindrical part of air venturi. 

If necessary adjust position by tapping pin (indicated) 
either upwards or downwards. 

Recheck position of sensor plate after refitting air-fuel 
control unit in vehicle. 



71 






Group 23 Fuel system 
Air-fuel control unit 



Fuel distributor 



Fuel distributor must not be disassembled. If any part is 
defective, complete unit must be replaced. It is however 
possible to clean control plunger 
Line pressure regulator can also be cleaned, O-rlngs 
and seals should be replaced. 




tossn 



D63 

Clean and check control plunger 

Always use clean gasoline and observe utmost 
cleanliness. 



Wash control plunger and blow clean with com- 
pressed air. Also clean metering slits. 



Make sure that plunger is not damaged, use non- 
metallic brush to remove dirt particles (on no account 
use metal tools). 



Install plunger in fuel distributor and check that it 
moves freely. If it binds, replace complete fuel 
distributor. 




Shim 



D64 

Clean and check line pressure regulator 

Use clean gasoline and observe utmost cleanliness. 
Disassemble and clean regulator. 

Replace worn or damaged parts. 

Caution! Pistons must not be replaced separately. If 
defective complete fuel distributor must be replaced. 
Assemble regulator and install, using new O-rings and 
seals. 



1978-1983 






D65 

Install fuel distributor on air-fuel sensor 

Use a new O-ring and make sure that it sits correctly. 
Take care that control plunger does not fall out and 
become damaged. 

Tighten screws evenly. Tightening torque 3.6 Nm (2.6 
ft. lb.). 



72 







Group 23 Fuel system 
Injectors 



INJECTORS 

Operations D66-75 




D66 

General 

Type of injector fitted to vehicle depends on engine 
type. Identification number is stamped on side of in- 
jectors. See table on page 75. 



067 

Fault symptoms: 

- erratic idling (fuel not atomised) 

- low top speed/poor engine performance (fuel not 
atomised) 

- misfiring while driving under heavy load 

- difficult to start hot engine (injectors do not seal 
which causes too low a rest pressure) 

- dieselling (injector opening pressure too low). 




D68 

Checking injectors 

Carry out the following operations B2, B8, B27-40. 



Replacing injectors 



New injectors are filled with a rustproofing com- 
pound. On storing, the compound hardens which is 
why injectors should always be cleaned and tested 
before installing (see method on next page). 

Check rubber seals and replace wherever necessary. 



Check idle speed and CO-content after replacing injec- 
tors. 

Note! Engine must be run at above idle speed to vent 
fuel lines. 



73 







Group 23 Fuel system 
Injectors 





Testing and cleaning injectors 

Operations D70-75 
Special tool: 9934 

Apparatus should be filled with solvents intended for 
cleaning purposes such as Shell K30, Esso-Versol, 
Shell Mineral spirits 135 or similar products. 

WARNINGI Never exceed a pressure of 600 kPa (85 
psi) during the test. 



D70 

Connect injector to tester 9934 

Use adapter P/N 243895-0. Do not tighten. 

Bleed pressure line by pumping until fuel free from air 
bubbles is supplied from fuel line. 

Then tighten connection. 



D71 

Check to see if injector is leaking 

Open pressure gauge cock. 

Pump slowly, about 2 seconds per sweep. Check that 
pressure rises to at least 100-150 kPa (14-21 psi). 

If not, injector is leaking and must be cleaned. See 
D72. 



D72 

Clean injector (whenever necessary) 

Pump strongly 15-20 times. Then repeat D71. 

If pressure is still too low, injector should be replaced. 



073 

Check opening pressure 

Close pressure gauge cock. 

Quickly pump a few times to vent injector. 

Open pressure gauge cock. 

Pump slowly, about 2 seconds per sweep. Record 
pressure when injector opens. 

See table at bottom of next page for opening 
pressures. 

If pressure is incorrect, replace injector. 



74 






Group 23 Fuel system 

Injectors 

D74 

Check injector 

Open pressure gauge cock. 

Increase pressure slowly to value indicated in table 
below. 

Keep pressure constant at this value. 

In a 15 second period injector must not drip. 

If injector drips, clean injector according to D72. 





D75 

Check injector function, spray pattern etc. 

Close pressure gauge cock. 

Pump at approx. 1 sweep per second for at least 10 
seconds and observe injectors. 

Correct injectors buzz and no drops form at the tip. The 
correct spray pattern is shown adjacent. 

If incorrect, clean injector according to D72. 






1975-1978 


1979-1983 


Injector, Bosch number 


005* 


. . . 013 


Volvo number 


269184-8 


1269274-5 


opening pressure 


300-360 kPa 


320- 380 kPa 




(42-50 psi) 


(45-53 psi) 


no leakage permitted below 


240 kPa 


260 kPa 




(34 psi) 


(36 psi) 



‘replacement part . . . 013 



75 





Group 23 Fuel system 
Control pressure regulator 



CONTROL PRESSURE REGULATOR 

Operations 076-79 






Illustration shows a control pressure regulator incorporat- 
ing acceleration enrichment system for cold engine 
IB 28 FI. 

Note! B 28 F USA and Canada with pressure differential 
switch: acceleration enrichment system via control 
pressure regulator is disconnected. 



D76 



General 

Type of control pressure regulator fitted to vehicles 
depends on engine type. They are identified by the last 
3 digits of the number stamped on top of regulator. 



Fault symptoms 



D77 



A defective control pressure regulator causes incor- 
rect control pressure which in turn causes an incorrect 
fuel-sir mixture. 



The following symptoms can arise: 

- difficult to start engine 

- erratic running, possibly stalling 

- excessive fuel consumption (low control pressure) 

- poor engine performance/low top speed 

- rough acceleration, backfiring 

- misfiring while driving under heavy load. 



D78 

Checking control pressure regulator 

Control pressure should be measured when engine is 
cold ie. below 30°C (86°F). 

Follow operations B1-3. B8, B15-21. 



D79 

Replacing control pressure regulator 

Allen key 5 mm. 

After replacing regulator, check control pressure, idle 
speed 8nd CO-content. 



/ "*S 






76 




Group 23 Fuel system 

Start injector, thermal time switch, impulse relay 



START INJECTOR, THERMAL TIME SWITCH, IMPULSE RELAY 

Operations D80-92 





130 45? 



D80 

General 

Type of start injector fitted to vehicle depends upon 
model year and engine type. Identification number is 
stamped on side of injector. 

Thermal time switch controls start injector when start- 
ing with a cold engine. Engagement time of start injec- 
tor at -20°C (-4°F) is stamped on collar of injector. 

B 27 F engines are equipped with a switch with a 15°C 
(59 = F| cut-out temperature. Replacement part for this 
switch has a cut-out temperature of 35°C (95 C F). 
Impulse relay is fitted to 1981-1982 ’models. It con- 
trols start injector during warm starts. 



‘Impulse relay may have been fitted to some B27 E 
1979-1980, B 27 F 1978-1979 and B 28 F 1980 models. 
See page 78. 



D81 

Fault symptoms: 

- difficult to start engine/does not start when cold 

- difficult to start when warm. 

A leaking start injector can cause excessively high fuel 
consumption, rough running and dieselling. 



Cold start problems B 27 F 1978-1979 
Replace thermal time switch with one with a cut-out 
temperature of 35‘C (95°F). This improves cold starting 
in temperature range 15*C - 35*C. 

Warm start probloms B 27 E 1979-1980, B 27 F 1978- 
1979 and B 28 F 1980 

Installation of an impulse relay improves warm start- 
ing, see page 78. 



D82 

Checking parts 

Start injector function should be checked when the 
engine is cold (below 30°C = 86 e F). 

Carry out operations B2, B5-10. 



77 






Group 23 Fuel system 
Installing impulse relay 




Installing impulse relay 

Operations 083-92 

Applies to: B 27 E 1979-1980. B 27 F 1978-1979. B 28 F 1980 



D83 

General 

Injection time of start injector is controlled by a ther- 
mal time switch. 

1981-1983 models also have an impulse relay to oper- 
ate start injector. 

Impulse relay engages start injector after approx. 1.5 
seconds with subsequent injection for 0.1 secs- pause 
0.3 secs - injection 0.1 secs etc. 

Additional fuel is therefore supplied during warm 
starts. 

Impulse relay can, if required, be fitted to vehicles 
manufactured before 1981. 

IMPORTANT! B 27 E 1979 Australia and B 27 F 1978- 
1979: evaporative system must be modified slightly 
before installing impulse relay. 



Wiring diagram 



Required parts 



Note! B 27 E Australia and 8 27 F 1978-1979: a dalay valve 
(P/N 1276311-6) is also required. 



Component 
A Impulse relay 
B Thermal time switch 
C Start injector 



Colour 
BL = blue 
W - white 
Y = yellow 



Description 


Qty 


P/N 


Wire 1.5 mm* 
while 


2250 mm 


954450-3 


blue 


1700+150 






mm 


954448-7 


PVC sheath 


1600 mm 


192598-1 


Cable terminal 


3 


949489-9 


Cable terminal 


1 


956925-2 


Clamp 


2 


944306-0 


Plug 


1 


1234066-7 


Impulse relay 


1 


1274396-9 



78 





Group 23 Fuel system 
Installing impulse relay 










D86 

Assemble wiring harness 

Do not attach clamps at this stage. 

15 cm - 6 in 
170 cm - 63 in 
225 cm - 89 in 

D87 

Disconnect/remove 

- ground lead from battery 

- air filter. 




r 

r 




D89 

Connect wiring harness for impulse relay 

Pull apart plastic covering on existing wiring harness. 
Connect new wiring harness. 

Slide cover back into position. 



D90 

Connect wiring harness 
Install impulse relay 

Reconnect plugs on existing wiring harness. 

Route wiring harness for impulse relay along existing 
wiring harness, to ignition system control unit. 
Secure wiring harness with clamps. 

Install impulse relay and connect wires. 

Do not forget the ground wire. 

IMPORTANTI Impulse relay must not be mounted on 
bulkhead/firewall because heat radiation from exhaust 
system can interfere with relay function. 




79 





Group 23 Fuel system 
Installing impulse relay 





Install: 

- air filter 

- battery lead. 






80 





Group 23 Fuel system 
Auxiliary air valve 



AUXILIARY AIR VALVE 



Operations D93-95 




0 280 140 .. . 

134 740 



Type of auxiliary air valve fitted to vehicle depends on 
model year and engine type. Identification number is 
stamped on end of valve. 

Vehicles equipped with Constant Idle Speed system 
are not fitted with an auxiliary air valve. 



B27E 1975-1978 



I 







D94 

Fault symptoms: 

- difficult to start engine/does not start when cold 

- idle speed too high (valve does not close) 



D95 

Inspection of auxiliary air valve 

Engine must be cold (below 30°C = 86°F) when in- 
specting valve. 

Carry out following operations: 

B2-3, B14, B26. 



81 




Group 23 Cl system 
Relays 



RELAYS 

Operations D96-98 

P/N 1214764-1 






1978-1983 

One relay (electronic). 



82 








Group 23 Fuel system 
Cl-system, wiring diagram 



E. Cl-system wiring diagram 

Note! All diagrams show current flow when engine is operating 




1975 

Fuse No. 4 

Glove compartment 
Heated driver seat 
Air conditioning 
Reversing/back-up light 



Fuse No. 7 

Clock 

Note! If vehicle is equip- 
ped with tank pump, fuse 
no. 7 should be 16A. 




Ignition switch 
Fusebox 

Control pressure regulator 
Fuel pump 
Tank pump 

Capacitor (integrated with tank 
gauge unit on some models) 
Main relay (1975-19771 
Pump relay (1975-1977) 
Transistorized pump relay 
(1979-1983) 

Starter motor 

Ignition coil 

Auxiliary air valve 

Thermal time switch 

Start injector 

Impulse relay (1981-1983) 

Control unit for ignition system 

Distributor 



■ black BN - brown OR** orange 
* grey Y =* yellow VO » violet 
= white BL = blue P = pink 
= red GN = green 



1976-1977 

Fuse No. 5 

Direction indicator 
Combined instrument 
Indicator and warning lamps 
Seat belt reminder 
Power door mirror 



Note! Main relay G and pump relay H are not same type, 

see page 82. 








Group 23 Fuel system 
Cl-system wiring diagram 




84 





Group 23 Fuel system 
Cl-system wiring diagram 




1981-1983 

Fuses No. 5 & 7 
No other functions 



Fuse No. 13 

Direction indicator 
Seat belt reminder 
Combined instrument 



Ignition switch 
Fusebox 

Control pressure regulator 
Fuel pump 
Tank pump 

Capacitor (integrated with tank 
gauge unit on some models) 

Main relay (1975-1977) 

Pump relay (1976-1977) 
Transistorized pump relay 
(1978-1983) 

Starter motor 
Ignition coil 
Auxiliary air valve 
Thermal time switch 
Start injector 
Impulse relay (1981-1983) 

Control unit for ignition system 
Distributor 

Colour code 
SB ■ black BN = brown 0R = orange 

GR - grey Y - yellow VO - violet 

W = white 8L - blue P - pink 

R = red GN - green 



85 






Microswitch ' 



Service connection 
1982 models only 
Blue-white wire Is sevice con- 
nection for CIS-system 
Red wire is for Lambda-sond 
system 



•1982 version shown above 
1981 version is slightly different 



IMPORTANT! "Idle adjustment" screw and balance 
screws must always be screwed in fully on engines 
with constant idle speed system. 

Balance screws are of shearhead type and must be 
tightened until heads break off. 





Group 23 Fuel system 

CIS system, idle speed - fault symptoms 



Idle speed 



rpm 

^ T ,J 



Cold engine <-20*C = 4°F> approx. 18 r/s (1100 r/min) 
Idle speed reduces as engine heats up and stabilizes at 
approx. 15“C (59*F) 



Warm engine 15 r/s (900 r/min) 

Tolerances: 

1981 14.2-15.8 r/s (850-950 r/min) 

1982 14.7-15.3 r/s (880-920 r/min) 



Fault symptoms 

Fault symptoms in system may be caused by external faults, see list below. 
Notel All symptoms can be caused by poor electrical contacts (e.g. oxide formation). 



FAULT SYMPTOM 


POSSIBLE CAUSE 


Idle speed fluctuates 


- ignition setting 

- CO-content 

- air leakage 


Idle speed too high 


- incorrectly adjusted microswitch 

- temperature sensor defective 
or not connected 

- throttle valve incorrectly set 


Idle speed too low 


- blocked air hoses 

- blocked crankcase ventilation 


No control 


- throttle valve incorrectly set 

- microswitch incorrectly set 


Engine stalls when braking to stop 


- ignition setting 

- CO-content 

- air leakage 


No fast idle, cold engine 


- temperature sensor defective 
or damaged cable. 







Ground service connection 

Air control valve closes 

IMPORTANTI Ground the blue-white wire. 

Red wire is service connection for Lambda-sond 
system. 



B28F1981 

Disconnect control unit 

Air control valve now takes up basic position. 
Ignition should be off. 

Withdraw white-red wire (terminal 12) from blue 
nector on control unit 



Connect a rev counter and start engine 

Note AC must be disengaged. 

Engage 'N" (auto). 



F. Basic setting and inspection of CIS system 



Engine should be warmed-up to normal operating temperature. 



FI 

Disconnect link rod from throttle pulley 

Ensure that pulley moves smoothly and does not bind. 



Group 23 Fuel system 

CIS system, basic-setting - checking 








Group 23 Fuel system 

CIS system, basic-setting - checking 









r 




F5 

Connect a test lamp to microswitch 

| 1982 version shown adjacent. 1 

Connect test lamp between 12V power source and: 



1981 yellow wire on microswitch 

1982 terminal 4 on microswitch 



Lamp should light and remain on throughout adjust- 
ment, otherwise setting will be incorrect Adjust if 
necessary with the upper adjustment screws. 





F6 



Basic-set throttle valves 

Make sure that idle adjustment screw is screwed in 
fully ie. bottoms. 

Adjust idle speed with lower adjustment screw to 14.2 
r/s (850 r/min). 



| IMPORTANT! Test lamp must remain on7 



] 



Connect control unit 



F7 



1981 

Turn off ignition. 

Connect white-red wire (terminal 12) to control unit. 
Start engine. 

1982 

Disconnect ground wire from service connection. 



rpm 

— 



F8 

Check idle speed 

When control unit is engaged idle speed should in- 
crease briefly and then stabilize at 15.0 r/s (900 r/min). 
Tolerances: 



1981 14.2-15.8 r/s (850-950 r/min) 

1982 14.7-15.3 r/s (880-920 r/min) 




Group 23 Fuel system 

CIS system, basic-setting - checking 




F9 

Check fast idle 

Turn off engine. 

Withdraw blue wire from connector on bulkhead. 
(This disengages temperature sensor and simulates 
cold start). 

Start engine. Engine speed should now be 26.6-40.0 
r/s (1600-2400 r/min). 

Reconnect blue wire. Engine speed should return to 
normal again. 

Turn off engine and disconnect rev counter. 



F10 

Adjust microswitch 

Insert a 0.3 mm (0.012 in) feeler gauge at lower 
adjustment screw. 

Unscrew upper adjustment screw until test lamp goes 
out. Then screw in until lamp just lights. 

Check setting with a 0.2 mm (0.008 in) and a 0.6 mm 
(0.024 in) feeler gauge. 

0.2 mm = lamp on 0.6 mm = lamp off 




F11 



Adjust throttle cable 

Throttle pulley should strike stop in idle position. Ca- 
ble should be taut but must not move throttle pulley. 
At full throttle, pulley should contact other stop. 




F12 

Adjust kick-down cable 

Depress accelerator to floor. 

Note! Do not adjust cable by hand otherwise setting 
will be incorrect. 

At full throttle, distance between cable sleeve and clip 
equals 50.4-52.6 mm (1.98-2.10 in). 



90 




Group 23 Fuel system 

CIS system, basic-setting - checking 




r 




F14 

Adjust microswitch at throttle pulley 

Connect test lamp between 12V power source and 
green wire on microswitch. 

Adjust microswitch to engage (lamp on) 2.5-1. 0 mm 
(0.1-0.04 in) before throttle pulley contacts full throt- 
tle stop. 



IMPORTANT! B 28 F USA vehicles for high altitude use: 
microswitch should be disconnected. 



r 

r 



91 






Group 23 Fuel system 
CIS system, fault tracing 



G. Fault tracing of CIS system 

It is assumed in the instructions below that the engine is In a good condition and that the ignition 
is correctly set 

See also wiring diagram on page 95. 

IMPORTANT! Ignition must be off when connecting/disconnecting electrical connections. 





Check air hoses 



G1 



Make sure that hoses are not kinked or damaged. 

If engine speed is far too low: 

Check hoses, nipples and air valve for blockages. 
Blockages can be caused by carbon deposits from 
engine crankcase. Check that oil has been changed 
according to specifications. Correct if necessary. 



G2 

Check electrical connections 

Note! Poor connections can cause many symptoms. 



G3 

Disconnect plugs from control unit 
Turn on ignition. 



G4 



Check current supply 

Connect a test lamp between terminal 1 and ground. 
1982 models: also connect test lamp between termi- 
nal 7 and ground. 

Lamp should light. If not, first check fuse No. 13. 



92 




Group 23 Fuel system 
CIS system, fault tracing 




G5 

Check ground connection 

Connect test lamp between terminals 1 and 2. 

Lamp should light. 



B28F 1982 



G6 

Check that service connection is not grounded 

Connect test lamp between terminals 1 and 10. 

Lamp should not light. 



r 

r~ 




G7 

Check microswitch 

Connect test lamp between terminals 1 and 8. 
Depress accelerator to floor and observe test lamp. 
Note! Microswitch function is different on 1981 and 
1982 models. 

Test lamp 1981 1982 

- accelerator UP (idle) ON off 

- accelerator depressed off ON 

1 » 4 » 






G8 

Check temperature sensor 

Connect an ohmmeter between terminals 9 and 11. 
Correct resistance at different temperatures is shown 
in diagram below. 

If incorrect, repeat measurement at temperature sen- 
sor. If in doubt, remove sensor and test at different 
temperatures. 




Suitable test temperatures: 

-10*C <14°F> 32000-530000 

+ 20“C (68°F| 8500-115000 

+80 C C |176°F) 770- 13200 



93 



Group 23 Fuel system 
CIS system, fault tracing 





G9 

Check signal from ignition coil 

Connect a rev counter to terminal 12. 

Start engine. Rev counter should indicate engine 
speed. 

Leave rev counter connected and engine running. 




G10 * 

Check air control valve 

Two short cables are needed for this test. 

Connect one between terminals 5 and 2 and the other 
between terminals 4 and 1. 

Engine speed must remain constant at 26.8-40.0 r/s 
( 1600-2400 r/min). 

A defective air control valve is indicated by low engine 
speed. 




G11 

Test with a new control unit 

If no fault is found in above tests, connect new control 
unit and retest. 



IMPORTANT! Turn off ignition when disconnecting/ 
connecting electrical connections. 



Bear in mind that different control units are used for 
1981 and 1982 models. 



94 





Group 23 Fuel system 
CIS system, wiring diagram 



H. Wiring diagram, CIS system 




95 






Group 23 Fuel system 
Idle, CO 



J. Idle speed and CO-content 
Checking/adjusting 




J1 

General 

It is important that the engine settings are correctly 
adjusted (e.g., timing) if valid results are to be ob- 
tained. 

The engine should be warm and idling. 

Warm-up the engine at 25 r/s (1500 r/min). 
Check/adjust the CO content 5 minutes (no earlier), 
after the radiator thermostat has opened. 




J2 

Exhaust gas extraction 

Use an exhaust gas extractor that fits loosely over the 
exhaust pipe, otherwise CO may be set incorrectly. 









96 



Group 23 Fuel system 
Idle. CO 



Idle speed and CO-content 



B 27 E 1975-1978 

Operations J3-7 
Special tool: 5102 




J3 

Connect test equipment 

- Tachometer (there is no service connection for Volvo 
Mono-Tester on 1975-1976 or early manufactured 
1977 models). 

- CO-meter. Probe should be inserted at least 480 mm 
(19 in) from end of exhaust pipe otherwise fresh air 
may mix with exhaust gases and cause false results. 



J4 

Set idle speed 

Engine must be warmed-up to operating temperature. 
Idle speed = 15.0 r/s (900 r/min). 



J5 

Check/adjust CO-content 

Engine warm and idling. 

Use tool 5102 to adjust CO-content. 

After each adjustment rev-up engine for a short while 
before checking CO-content. 

CAUTIONI Remove 5102 otherwise air-fuel control 
unit may be damaged. 

- Anti-clockwise (left) reduces CO-content 

- Clockwise (right) increases CO-content 
Refit plug after adjusting CO. 

CO-content Check Setting 

value value 

1975-1977 

Sweden + Australia . . 1. 0-4,0 1.5 

Other markets 1.0-4.0 2.0 

1978 1 .0-3.0 2.0 

J6 

Check/adjust idle speed 
15.0 r/s (900 r/min). 



J7 

Remove measuring equipment 

Turn off engine. 



97 






Group 23 Fuel system 
Idle, CO 



Idle and CO content 

B 27 E 1979-1980, B 28 E 

Operations J8- 15 
Special tool: (2901) 5102 






98 




Group 23 Fuel system 
Idle. CO 




J11 

Check/adjust CO-content 



CO-content, checking 1.0-3.0% 

setting 2.0% 



Use wrench 5102 to adjust CO-content. 

- anti-clockwise (left) reduces CO-content. 

- clockwise (right) increases CO-content. 



After each adjustment rev-up engine for a short while 
before checking CO-content. 

CAUTIONI Remove 5102 otherwise air-fuel control unit 
may be damaged. 



Refit plug after adjusting CO. 




J12 

Basic-setting of balance screws 

Balance screws need only be reset if idle is rough on 
condition that all other engine controls are correctly 
set. 

Screw in both balance screws (2 and 3) fully to bottom 
position. Then unscrew: 

- screw 2 (left bank = cylinders 1, 2, 3) 1.5 turns 

- screw 3 (right bank = cylinders 4, 5, 6) 5.0 turns. 
Adjust idle speed and CO-content according to J10-11. 




J15 

Disconnect test equipment 

Turn off engine. 



99 





Group 23 Fuel system 
Idle , CO 



Idle and CO-content 

B 27 F and B 28 F 

Operations J16-30 
Special tools 5102, 5151 

5232 USA 1931-1982, Canada 19821 





• Lambda-sond system 

B 27 F 1978 USA California + Japan 
1979 All models 
B 28 F 1980-1982 All models 



Illustration on left shows frequency valve in lambda- 
sond system. 



• Constant idle speed system 
B 28 F 1981 USA California -I- Japan 
1982 All models 

| Illustration shows air control valve in CIS-system. 



100 







Group 23 Fuel system 
Idle, CO 




J16 

Connect test equipment 

- rev counter 

- CO-meter. Connect to adapter 5151, lever should be 
in centre position. 



J17 

Check/adjust idle speed 

Warm engine. Adjust with screw 1. 

B 27 F 1977 California 15.8 r/s (950 r/minj 

B 28 F 1980 15.8 r/s {950 r'min) 

Other markets 15.0 r/s (900 r/min) 




IMPORTANT! 

The following applies for engines equipped with 
CIS-system 

- idle adjustment screw {1) must be screwed in fully 

- balance screws (2 & 3) are of shear-head type and 
must be screwed in until heads break off. 

- if idle speed is incorrect, CIS-system must be 
checked and basic-set whenever necessary. See 
FI-14, page 88. 




Engines with air pump J18 

Disconnect air pump: 

Disconnect hose from air pump. 

Plug hose or block hose with clamps 2901 (safety pre- 
caution). 



Engines with lambda-sond system J19 

Disconnect lambda-sond 



Lambda-sond 



101 




Group 23 Fuel system 
Idle. CO 




J20 



Check CO-content 

Adapter lever (5151) must be in centre position: 



Checking 

value 

B 27 F 1976 1. 4-2.0% 

1977 USA Calif 0.4- 1.0% 

1977 USA Fed 0.7- 1.3% 

1977 Canada + Japan 1.4~2.0% 

1978-1979 0.7 -1.3% 

8 28 F 1980-1982 0.7- 1 .3% 





J21 

Adjust CO-content (as applicable) 

Use wrench 5102. 

- Anticlockwise (left) reduces CO-content 

- Clockwise (right) increases CO-content. 



After each adjustment: remove wrench 5102 and cover 
hole in air-flow sensor for CO-adjustment. Rev-up 
engine briefly. If this is not done, incorrect results will 
be obtained. 



Idle speed must b« correct when checking the CO- 
content, adjust if necessary. 



Setting 

value 

B 27 F 1976 1.7% 

1977 USA California 0.7% 

1977 USA Federal 1.0% 

1977 Canada + Japan 1.7% 

1978-1979 1.0% 

B 28 F 1980-1982 1.0% 



Cars without CO adjustment seal: 
Refit plug after adjusting CO. 



102 






Group 23 Fuel system 
Idle, CO 



r 

r 



r 

r 




Checking/adjusting CO balance 



IMPORTANT! Nol applicable to engines with CIS- 
system. 



Operations J22-24 



Balance screws need only be reset if idle is rough, on 
condition that all other engine controls are correctly 
set. 



Idle adjustment screw 1 allows a certain amount of air 
to pass by. This air is divided between both cylinder 
banks, and balanced by screws 2 and 3. 

Screw 2 is for left bank = cylinders 1, 2 and 3. 

Screw 3 is for right bank = cylinders 4, 5 and 6. 



J22 

Basic-set balance screws 

Only necessary if engine running is very rough. 
Screw in screws 2 and 3 fully. 

Then unscrew screw 2-1.5 turns and 3-5 turns. 




J23 

Check/adjust CO balance 

Set lever on adapter 5151 to point towards left cylinder 
bank. 

Record CO-content. 

Turn lever to point towards right cylinder bank. 
Record CO content. 

CO content should be same for both cylinder banks. 
Adjust by screwing in screw for bank with lowest CO. 
Example 

Screwing in screw 2 will reduce air-flow to left cylinder 
bank and cause CO to increase. Air-flow to right bank 
will accordingly increase, and CO decrease. 



J24 

Check/adjust CO-content 

Check/adjust CO for both cylinder banks together. If 
necessary refer to J20-21. 

Adapter lever 5151 should be in center position. 



103 






Group 23 Fuel system 
Idle, CO 




Engines with air pump J25 

Connect hose to air pump. 

When hose is connected CO-content should drop in- 
dicating that system is functioning. 



J26 

Engines with Lambda-sond system: 

When Lambda-sond is connected the CO should drop 
to less than 1.0%, indicating that system is function- 
ing. 




J27 

Check/adjust idle speed 

Adjust screw 1 

B 27 F 1977 California 15.8 r/s (950 r/min) 

B 28 F 1980 15.8 r/s (950 r/min) 

Other markets 15.0 r/s (900 r/min) 

Note! Engines with CIS-system: idle adjustment 
screw (1) must be screwed in fully. 

J28 

Turn off engine 




104 







Group 23 Fuel system 
Air filter, air pre-heating 



K. Miscellaneous 

Air filter, air pre-heating 



Operations K1-4 




105 






Group 23 Fuel system 
Air filter, preheating 



B 27 E 1979-1980, B 28 E, B 27 F 1979, B 28 F 





K4 

Shutter housing for air pre-heating 

Position of shutter at different temperatures can be 
checked by observing ends of spindle, see fig. For a 
more exact check, it is necessa ry to remove the shutter 
housing and test the thermostat in warm water. 

If defective, replace the complete shutter housing and 
thermostat. 










Shutter positions: 
a hot air only up to 15°C (S9°F) 
b intermediate 

c cold air only = from 25*0 (77°F) 



106 





Group 23 Fuel system 
Fuel lines 



Fuel lines 

Operations K5-19 

Replacing nipples in fuel lines (plastic hoses) 

Special tools: 5012, 5013 




K5 

Always use new nipples when reconnecting fuel lines 
since sealing surfaces of the nipples are easily 
damaged on removal. 

To fit a new nipple, cut fuel line at right angles approx. 
20 mm (0.8 in) from adapter. 

Cut a slit in the outer shielding hose approx. 40-50 
mm (1.6-2. 0 in) long. 

Remove dirt from fuel line and blow clean. 

Use pliers 5012 (5013 for larger sizes) as shown. Heat 
fuel line with hot air, eg. use a hair dryer, and press in 
the new nipple. White spirit can be used as a lubricant. 
Fold back the outer shielding hose and fit a strip 
clamp. 



Replacing fuel line between fuel accumulator and fuel filter 

(Right hand drive vehicles: from fuel accumulator to connecter on firewall) 

1978-1982 models only 




K6 

In March 1982 one-piece polyamide plastic fuel lines 
were introduced into production instead of steel fuel 
lines. 

This was done primarily for economical reasons but 
fuel injection engines have also benefited by a reduc- 
tion In noise level from fuel pump. 

Only the new type of fuel line will be stocked by the 
Parts Department for 1978- vehicles. 

See next page for replacement method. 



Required parts 

Fuel line 

Clamp 

Strip clamp . . . 
Hollow screw . 
Seal (2x) 



Left hand drive 

1312287-4 

1221990-3 

948211-8 

25167-8 

18671-8 



Right hand drive 

1312286-4 

1221990-3 



107 




Group 23 Fuel system 
Fuel lines 




Left hand drive vehicles 

Operations K7-9 



K7 

Disconnect fuel line and elbow connecter from 
fuel filter 

First unscrew fuel tank cap to release pressure from 
fuel tank (reduces spillages). 

Remove dirt from connections before disconnecting 
fuel line. 



USA 1979-, Other markets 1980- 

K8 

Cut out a piece of fuel filter bracket 

This is necessary to prevent fuel filter from turning 
when fuel line is connected. File edges on bracket. 








Right hand drive vehicles 

K10 

Connect new fuel line to junction on firewall 

Unscrew fuel tank cap to release pressure from fuel 
tank (reduces spillages). 

Clean connections before disconnecting fuel line. 
Tape over end of fuel line to prevent dirt from entering. 
Route fuel line alongside existing one. 

Connect fuel line. 



108 




Group 23 Fuel system 
Fuel lines 



Left and Right hand drive vehicles 



Remove old fuel line. 



K11 




K12 

Connect new fuel line to fuel accumulator 
Fit clamps 

Start at rear and clamp fuel line with old clamps. Do 
not fit front clamp at this stage. 

Fit a new clamp (arrowed). 



r 



r 




K13 



Fit front clamp 

Move clamp approx. 35 mm (1.4 in) downwards in 
relation to old position. Drill a 3.5 mm (0.14 in) hole for 
clamp. 



Left hand drive vehicles 

K14 

Clamp fuel line to return line beneath steering 
column 

Use strip clamps. 



r 



109 




Group 23 Fuel system 
Fuel tank 



Fuel tank types 

Three different types of fuel tanks have been fitted to vehicles manufactured between 1975 
and the middle of 1978. The difference between the types lies in the location of the tank 
sender unit and splash can in the tank, and also in the attachment of the tank sender unit. 




K20 

Type 1 

1975 -middle of 1977. 

Model Chassis number 

262 — 2429 

264 -* 37729 

265 -» 9092 

Manufactured without a tank pump. May have later 
been fitted with a tank pump. 



K21 



Type 2 

Middle of 1977 - end of 1977. 

Model Chassis number 
262 2430-2659 

264 37730-46514 

265 9093-10919 

Tank pump introduced in production. 

Position of sender unit and splash can changed. 



K22 



Type 3 

Beginning of 1978 - middle of 1978. 
Model Chassis number 

262 2660-3362 

264 46515-52131 

265 10920-12594 

Modified attachment of tank sender unit. 



115 




Group 23 Fuel system 
Fuel tank 



Replacement of fuel tank 

Operations K23-43 



Type 1 fuel tanks: only one type of replacement tank is 
available P/N 1255740-1. Old parts can be transferred 
to the new tank. 

Type 2 fuel tanks: only one type of replacement tank is 
available P/N 1255739-3. Old parts can be transferred 
to new tank. 

Type 3 fuel tanks: no longer stocked, new type now 
available. For fitting the new type of tank to older 
vehicles, it is necessary to replace a number of parts. 
See below for the parts required. 

For working procedures, see page 118. 



K24 

Other markets (all markets except USA) 

Only the late type fuel tank is stocked (see page 122). 
For fitting the new type of tank to older vehicles, it is 
necessary to replace a number of parts. 

See below for the parts required. 

For working procedures, see page 118. 






Parts required when fitting 
a new type of fuel tank 



Item 

No. 


Description 


P/N 


Qty. 


Fuel tan 


k incl. filter tube 






1 


Filler hose 


1304240-3 


1 


2 


Filler tube 


1255189-1 


1 


3 


Clip 


948211-8 


2 


4 


Rubber seal 


1254461-1 


1 


5 


O-ring 


949282-8 


1 


6 


Screw 


955274-6 


1 


7 


Clip 


1254606-5 


1 


8 


Fuel tank 


1255754-2 


1 


Level se 


nder and tank pump 






1 


Lock ring 


1235324-9 


1 


2 


O-ring 


949276-0 


1 


3 


Level sender 


1258854-7 


1 


4 


Hose 


1235388-4 


1 


5 


Screw 


947279-6 


1 


6 


Spring clip 


942866-5 


1 


7 


Filter 


1266822-4 


1 


8 


Bracket 


1235444-6 


1 


9 


Tank pump 


1276330-6 


1 


10 


Washer 


940121-7 


2 


11 


Nut 


1266390-2 


2 


12 


Clip 


647709-5 


1 


13 


Sealing sleeve 


687245-1 


1 


14 


Hose clip (1975 only) 


948210-0 


1 


15 


Nipple (1975 only) 


947411-2 


1 



Item 

No. 


Description 


P/N 


Qty. 


Also required for 1975- 1977 models 




without 


r tank pump 






1 


Hose 


943707-0 


350 mm 


2 


Moulding 


679754-5 


100 mm 


3 


Hose protector 


1254913-5 


1 


4 


Clip 


943472-1 


4 


5 


Tube 


1254611-5 


1 


6 


Hose 


1229049-0 


1 


7 


Clip 


948211-8 


1 


— 


Fuse holder 


949611-4 


1 


- 


Fuse 


5 A 


1 


- 


Fuse (1975 only) 


16 A 


1 


— 


Connector 


247780-3 


1 


- 


Cable terminal 


958203-2 


1 


Evapora 


tive system 






1 


Clip 


946709-3 


2 


2 


Hose 


192034-7 


1150 mm 


3 


Bundy tube (262/264) 


944314-1 


1800 mm 


3 


Bundy tube (265) 


944314-1 


900 mm 


4 


Clip 


192248-3 


1 


5 


Grommet 


941264-4 


1 


6 


Clip 


1254513-3 


1 



100 mm = 4 in 
350 mm = 13.8 in 
800 mm = 31.5 in 
900 mm = 35.4 in 
1150 mm = 45.3 in 



116 



Group 23 Fuel system 
Fuel tank 



Installing a new type fuel tank 

Operations K25-43 
Special tools: 5012 (1975), 5169 






K25 

Pull down old fuel tank 

As a safety precaution disconnect battery. 

Drain fuel. 



K26 

Drill a hole for evaporative system tube 

Drill a 19 mm (0.75 in) hole in floor panel 70-80 mm 
(2.75-3.15 in) from the hole for the filler tube. 

Install rubber grommet. 



K27 

Assemble new tank/pump unit and tank pump 

Place filter so that it does not obstruct movement of 
float. 



1975 models only 



K28 



Replace return line nipple 

Cut off line approx. 20 mm (0.8 in) from nut. Cut a slit 
approx. 40-50 mm (1.6-2.0 in) along protective hose. 
Attach pliers 5012 to hard plastic hose. 



Heat hose with warm air (eg. hair dryer) and press in 
the new nipple. 

Fold back protective hose and secure with a clamp. 









118 





Group 23 Fuel system 
Fuel tank 




K29 

Install tank/pump unit in new fuel tank 

Use a new O-ring, lubricate it with gylcerine or similar. 
Install lock-ring with tool 5169. 




K30 

Seal breather nipple on tank/pump unit 

Use a sealing sleeve and clip. 

Note! Does not apply to vehicles which have a fuel 
accumulator with a fuel leakage line. 




1975-1977 models only 



K31 



Transfer following parts to new tank: 

Fuel pump and mounting bracket, fuel accumulator, 
hoses and moudling. 

Connect "suction" line to tank/pump unit. 

Cars already equipped with tank pump have these 
parts. Cars without must be so equipped. 




K32 

Connect filler tube 

Turn tube so that small inner tube for evaporative 
system points upwards. 





aim op £ 



Group 23 Fuel system 
Fuel tank 




K33 



Install rubber seal on filler tube 

Remove backing paper before pressing on seal. 

Joint on seal should point diagonally downwards and 
backwards. 

Attach two strip clamps. Cut off pieces not used. 
8-10 mm = 0.3-0.4 in 



K34 

Coat top of tank with a rustproofing compound 

Position tank in car. 

Connect delivery and return lines. 

40 mm = 1.6 in 




35 mm = 1.4 in 
300 mm = 11.8 in 
460 mm = 18 in 
560 mm = 22 in 



120 





Group 23 Fuel system 
Fuel tank 




Connect battery and start engine 



Check that: 

- there are no leaks 

- fuel gauge functions 

- tank pump functions. 



K41 



K42 

Install console panels and mat in boot/trunk 



Rustproof bottom of fuel tank 



K43 



121 






Group 23 Fuel system 
Fuel tank 



Fuel tank, middle of 1978-1983 

Operation K44 




122 





Group 23 Fuel system 



Evaporative system 



Evaporative system 

Operations K45-54 



Open evaporate system 



All markets excl. USA, Canada, Japan and Auatralia. 



Connection ot equalizing valve 
Not all year models 



Hose is clamped in different ways 
depending on model year 





Group 23 Fuel system 
Evaporate system 



Closed evaporative system 

USA Canada, Japan and Australia 
Operations K46-54 



Connection of equalizing valve and roll-over valve 

Equalizing valve was discontinued in 1980 and replaced by roll-over valve. 






Group 23 Fuel system 
Index 



Index 





Operation 


Page 




Operation 


Page 


Adjustments 






CO-content, checking/adjusting 






rest pressure 


B 64 


47 


general 


J 1-2 


96 


line pressure 


B 64 


47 


B 27 E 1975-1978 


J 3-7 


97 








1979-1980 


J 8-15 


98 


Air filter. 






B 28 E 


J 8-15 


98 


air preheating 1975-1978 


K 1-2 


105 


B 27 F 


J 16-30 


100 


1979-1983 .... 


K 3-4 


106 


B 28 F 1980-1982 


J 16-30 


102 


Air fuel control unit 






Constant Idle Speed system (CIS) 








D 22 


61 










D 23 


61 








B 27 E 1975-1978, removing . 


D 25-27 


62 


fault symptoms 




87 


installing . 


D 28-33 


62 


basic-setting and checking . . . 


F 1-14 


88 


reconditioning . . . 


D 34-46 


64 


fault tracing 


G 1-11 


92 




D 47 


68 




H 1 


95 


installing 


0 48-52 


68 


« w 




reconditioning . . 


0 53-65 


70 


Control pressure regulator 












general 


D 76 


76 


Auxiliary air valve 






fault symptoms 


D 76 


76 


general 


D 93 


81 


checking 


D 78 


76 


fault symptoms 


D 94 


81 








checking 


0 95 


81 


Evaporative system 












open 


K 45 


123 


Basic setting 






closed 


K 46-54 


124 


idle speed 


F 1-14 


88 














Fault symptoms 






Cl -system 






Cl-system 




49 


function 




14 


Constant Idle Speed system . 




87 


component location 




16 








flushing 


A1-18 


19 


Fault tracing 






inspection 


B 1-45 


24 


Cl-system 


C 1-2 


48 


fault tracing 


C 1-2 


48 


Constant Idle Speed system . 


G 1-11 


92 


wiring diagram 


El-5 


83 














Flushing fuel system 


A 1-18 


19 


CIS-system 












See constant Idle Speed system 






Fuel accumulator 












fault symptoms 


D 11 


55 


CO Balance screws 






checking 


D 12 


55 


B 27 E 1979-, B 28 E 


J 12 


99 


replacement 1975-1977 


D 13-16 


55 


B 27 F 


J 22-24 


103 


1978-1983 


D 13, 17-18 


55 


B 28 F 


J 17. 22-24 101 









130 




Group 23 Fuel system 
Index 





Operation 


Page 




Operation 


Page 


Fuel filter 






Non return valve (fuel pump) 






fault symptoms 


D 19 


60 


fault symptoms 


O 11 


55 


checking 


D 20 


60 


checking 


D 12 


55 


replacement 


D 21 


60 


replacement 1975-1977 


D 13-16 


55 








1978-1979 


D 13, 17 


55 


Fuel lines 






1980- 


D 13. 18 


55 


replacement, nipples 


K 5 


107 








replacement, lines 


K 6-14 


107 


Relays 


D 96-98 


82 


routing B 27 E 1975-1978.... 


K 15-16 


110 








1979-1980... 


K 19 


113 


Rest pressure 






B 27 F 1976-1977 .... 


K 17 


111 


adjusting 


B 64 


47 


1978 


K 18 


112 






1979 


K 19 


113 


Special tools 




12 


B28E/F 


K 19 


113 


Specifications 




2 


Fuel pump 




55 








fault symptoms 


D 11 


Start injector 






checking 


0 12 


55 


general 


D 80 


77 


replacement 1975-1977 


D 13-16 


55 


fault symptoms 


D 81 


77 


1978-1983 


D 13, 17-18 55 p 


checking 


D 82 


77 


Fuel tank 




114 


Tank pump 






1975-1978 different types . . 


K 20-22 


general 


D 1 


50 


replacement 


K 23-43 


116 


fault symptoms 


D 2 


50 


1978-1983 


K 44 


122 


checking 


D 3 


50 








replacement, type 1 


D 4-6 


50 


Idle speed, checking/adjusting 






type 2 

type 3 


D 4, 7-8 
D 4, 9-10 


50 

50 


general 


J 1-2 


96 


B 27 E 1975-1978 

1979-1980 

B 28 E 

B 27 F 

B 28 F 


J 3-7 
J 8-15 
J 8-15 
J 16-30 
J 16-30 


97 

98 
98 

100 

100 


Thermal time switch 

general 

fault symptoms 

checking 


D 80 
D 81 
D 82 


77 

77 

77 


Impulse relay 

general 


D 80 


77 


Wiring diagram 
Cl-system: 

1975 


E 1 


83 


fault symptoms 

checking 


O 81 
D 82 


77 

77 


1976-1977 

1978 ... 


E 2 
E 3 


83 

84 


installing 


D 83-92 


78 


1979-1980 


E 4 


84 


Injectors 

general 






1981-1983 


E 5 


85 


D 66 


73 


Constant Idle Speed system . 


H 1 


95 


fault symptoms 


D 67 


73 








checking 


D 68 


73 








replacement 


D 69 


73 








checking/cleaning 


D 70-75 


74 








Inspection 












Cl-system 


B 1-45 


24 








Constant Idle Speed system . 


F 1-14 


88 








Line pressure 












adjustment 


B 64 


47 









131 





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